Abstract

Micropub is an open API standard used to create posts on one's own domain using third-party clients. Web apps and native apps (e.g., iPhone, Android) can use Micropub to post short notes, photos, events or other posts to your own site.

Author's Note

This section is non-normative.

This specification was contributed to the W3C from the IndieWeb community. More history and evolution of Micropub can be found on the IndieWeb wiki.

Status of This Document

This section describes the status of this document at the time of its publication. Other documents may supersede this document. A list of current W3C publications and the latest revision of this technical report can be found in the W3C technical reports index at http://www.w3.org/TR/.

This document was published by the Social Web Working Group as a Working Draft. This document is intended to become a W3C Recommendation. If you wish to make comments regarding this document, please send them to public-socialweb@w3.org (subscribe, archives). All comments are welcome.

Please see the Working Group's implementation report.

Publication as a Working Draft does not imply endorsement by the W3C Membership. This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in progress.

This document was produced by a group operating under the 5 February 2004 W3C Patent Policy. W3C maintains a public list of any patent disclosures made in connection with the deliverables of the group; that page also includes instructions for disclosing a patent. An individual who has actual knowledge of a patent which the individual believes contains Essential Claim(s) must disclose the information in accordance with section 6 of the W3C Patent Policy.

This document is governed by the 1 September 2015 W3C Process Document.

1. Introduction

This section is non-normative.

Micropub is a spec to create content on a server using web or native app clients. Micropub is primarily focused around creating "posts" (individual pieces of content such as blog posts, photos, short notes, or responses) on a website, although it can be used for other kinds of content as well. The Micropub spec defines a simple mechanism to create content, as well as a more thorough mechanism to update and delete content.

1.1 Social Web Working Group

Micropub is one of two client APIs being produced by the Social Web Working Group with slightly different use cases and approaches. Interested implementers should check out and review the other approach, ActivityPub, as well.

1.2 Background

The Micropub vocabulary is derived directly from the [Microformats2] vocabulary. Micropub is meant to be a serialization of Microformats that can be submitted as an HTTP POST. The method for developing new Micropub vocabularies is to look at the Microformats representation and work backwards.

2. Conformance

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", " SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119].

2.1 Conformance Classes

This section describes the conformance criteria for Micropub clients and servers.

2.1.1 Publishing Clients

A conforming Micropub client that creates posts:

  • MUST support sending x-www-form-urlencoded requests
  • MUST support the [h-entry] vocabulary
  • If the client creates posts by uploading file attachments, it MUST check for the presence of a Media Endpoint and if present, send the file there instead of to the Micropub endpoint
  • SHOULD handle server error messages gracefully, presenting helpful messages to the user
  • SHOULD support endpoint discovery given an [IndieAuth] identity URL

2.1.2 Editing Clients

A conforming Micropub client that edits posts:

  • MUST support sending JSON-encoded requests
  • MUST support the [h-entry] vocabulary

2.1.3 Servers

A conforming Micropub server:

  • MUST support both header and form parameter methods of authentication
  • MUST support creating posts with the [h-entry] vocabulary
  • SHOULD support updating and deleting posts
  • If the server does not specify a Media Endpoint, then it MUST support x-www-form-urlencoded requests for creating posts

2.2 Candidate Recommendation Exit Criteria

For this specification to exit the CR stage, there must be at least two independent, interoperable implementations of each feature. Each feature may be implemented by a different set of products. There is no requirement that all features be implemented by a single product. For the purposes of this criterion, we define the following terms:

2.2.1 Client

A Micropub Client is an implementation that sends Micropub requests to create or otherwise manipulate posts. The conformance criteria are described in Conformance Classes above.

2.2.2 Server

A Micropub Server is an implementation that can create and optionally edit and delete posts given a Micropub request. The Micropub server MAY also support a Media Endpoint for handling file uploads outside of the primary Micropub endpoint. The conformance criteria are described in Conformance Classes above.

2.2.3 Independent

Each implementation must be developed by a different party and cannot share, reuse, or derive from code used by another qualifying implementation. Sections of code that have no bearing on the implementation of this specification are exempt from this requirement.

2.2.4 Interoperable

A Client and Server implementation are considered interoperable for a specific feature when the Server takes the defined action that the Client requests, the Client gets the expected response from a Server according to the feature, and the Server sends the expected response to the Client.

2.2.5 Implementation

An Implementation is a Micropub Client or Server which meets all of the following criteria:

  • implements the corresponding conformance class of the specification
  • is available to the general public, as downloadable software or as a hosted service
  • is not experimental (i.e. is intended for a wide audience and could be used on a daily basis)
  • is suitable for a person to use as his/her primary implementation on a website

2.2.6 Feature

For the purposes of evaluating exit criteria, each of the following is considered a feature:

  • Discovering the Micropub endpoint given the profile URL of a user
  • Authenticating requests by including the access token in the HTTP Authorization header
  • Authenticating requests by including the access token in the post body for x-www-form-urlencoded requests
  • Limiting the ability to create posts given an access token by requiring that the access token contain at least one OAuth 2.0 scope value
  • Creating a post using x-www-form-urlencoded syntax with one or more properties
  • Creating a post using JSON syntax with one or more properties
  • Creating a post using x-www-form-urlencoded syntax with multiple values of the same property name
  • Creating a post using JSON syntax with multiple values of the same property name
  • Creating a post using x-www-form-urlencoded syntax including a nested Microformats2 object
  • Creating a post using JSON syntax including a nested Microformats2 object
  • Uploading a file to the specified Media Endpoint
  • Creating a post with a file by sending the request as multipart/form-data to the Micropub endpoint
  • Returning HTTP 201 Created and a Location header when creating a post
  • Returning HTTP 202 Created and a Location header when creating a post
  • Updating a post and replacing all values of a property
  • Updating a post and adding a value to a property
  • Updating a post and removing a value from a property
  • Returning HTTP 200 OK when updating a post
  • Returning HTTP 201 Created when updating a post if the update cause the post URL to change
  • Returning HTTP 204 No Content when updating a post
  • Deleting a post using x-www-form-urlencoded syntax
  • Deleting a post using JSON syntax
  • Undeleting a post using x-www-form-urlencoded syntax
  • Undeleting a post using JSON syntax
  • Uploading a photo to the Media Endpoint and using the resulting URL when creating a post
  • Querying the Micropub endpoint with q=config to retrieve the Media Endpoint and syndication targets if specified
  • Querying the Micropub endpoint with q=syndicate-to to retrieve the list of syndication targets
  • Querying the Micropub endpoint for a post's source content without specifying a list of properties
  • Querying the Micropub endpoint for a post's source content looking only for specific properties

2.3 Test Suite and Reporting

Please submit your implementation reports at http://micropub.net/implementation-reports/. Instructions are provided at the URL. The implementation report template references the tests available at micropub.rocks.

micropub.rocks provides many test cases you can use to live-test your implementation. It also is a good tool to use while developing a Micropub implementation, as it provides detailed responses when errors are encountered.

3. Syntax

As [microformats2-parsing] has a relatively small ruleset for parsing HTML documents into a data structure, Micropub similarly defines a small set of rules to interpret HTTP POST and GET requests as Micropub commands. Where [microformats2-parsing] does not require changing the parsing rules to introduce new properties of an object such as an [h-entry], Micropub similarly does not require changing parsing rules to interpret requests that may correspond to different post types, such as posting videos vs "likes".

The Micropub syntax describes how to interpret HTTP POST and GET requests into useful server actions.

3.1 Overview

All Micropub requests to create posts are sent as x-www-form-urlencoded, multipart form-data [HTML5], or [JSON]-encoded HTTP requests. Responses typically do not include a response body, indicating the needed information (such as the URL of the created post) in HTTP headers. When a response body is necessary, it SHOULD be returned as a [JSON] encoded object.

3.2 Reserved Properties

A few POST body property names are reserved when requests are sent as x-www-form-urlencoded or multipart form data.

When creating posts, all other properties in the request are considered properties of the object being created.

Note

The server MUST NOT store the access_token property in the post.

3.3 Create

To create a post, send an HTTP POST request to the Micropub endpoint indicating the type of post you are creating, as well as specifying the properties of the post. If no type is specified, the default type [h-entry] SHOULD be used. Clients and servers MUST support creating posts using the x-www-form-urlencoded encoding, and MAY also support creating posts using the JSON syntax.

h={Microformats object type}

e.g., h=entry

All parameters not beginning with "mp-" are properties of the object being created.

e.g., content=hello+world

To specify multiple values for a property, such as multiple categories of an h-entry, use array bracket notation for the property name.

e.g., category[]=foo&category[]=bar

Properties that accept multiple values MUST also accept a single value as a string. A complete example of a form-encoded request follows.

Example 1
h=entry&content=hello+world&category[]=foo&category[]=bar

3.3.1 Uploading Files

To upload files, the client MUST check for the presence of a Media Endpoint. If there is no Media Endpoint, the client can assume that the Micropub endpoint accepts files directly, and can send the request to it directly, To upload a file to the Micropub endpoint, format the whole request as multipart/form-data and send the file(s) as a standard property.

For example, to upload a photo with a caption, send a request that contains three parts, named h, content and photo.

Example 2
multipart/form-data; boundary=553d9cee2030456a81931fb708ece92c

--553d9cee2030456a81931fb708ece92c
Content-Disposition: form-data; name="h"

entry
--553d9cee2030456a81931fb708ece92c
Content-Disposition: form-data; name="content"

Hello World!
--553d9cee2030456a81931fb708ece92c
Content-Disposition: form-data; name="photo"; filename="aaronpk.png"
Content-Type: image/png
Content-Transfer-Encoding: binary

... (binary data) ...
--553d9cee2030456a81931fb708ece92c--

For properties that can accept a file upload (such as photo or video), the Micropub endpoint MUST also accept a URL value, treating that the same as if the file had been uploaded directly. The endpoint MAY download a copy of the file at the URL and store it the same way it would store the file if it had been uploaded directly. For example:

Example 3
h=entry&content=hello+world&photo=https://photos.example.com/592829482876343254.jpg

This is to support uploading files via a Media Endpoint, or by reference to other external images. See the Media Endpoint section for more information.

Note

The Accessible Platform Architectures Working Group has raised an issue requesting examples of how to include accessibility-related information such as image alt text when creating posts that contain an image. Please see Issue 34 to track the progress of this issue.

3.3.2 JSON Syntax

Alternately, you can create a post with JSON syntax by sending the entry in the parsed Microformats 2 JSON format.

Note that in this case, you cannot also upload a file, you can only reference files by URL as described above.

When creating posts in JSON format, all values MUST be specified as arrays, identical to the Microformats 2 JSON format.

Example 4
{
  "type": ["h-entry"],
  "properties": {
    "content": ["hello world"],
    "category": ["foo","bar"],
    "photo": ["https://photos.example.com/592829482876343254.jpg"]
  }
}

3.3.3 Nested Microformats Objects

Whenever possible, nested Microformats objects should be avoided. A better alternative is to reference objects by their URLs. The most common example is including an h-card for a venue, such as checking in to a location or tagging a photo with a person or location. In these cases, it is better to reference the object by URL, creating it first if necessary.

This technique has the advantage of ensuring that each object that is created has its own URL (each piece of data has its own link). This also gives the server an opportunity to handle each entity separately. E.g., rather than creating a duplicate of an existing venue, it may give back a link to one that was already created, possibly even merging newly received data first.

In some cases, it does not make sense for the nested object to have a URL. For example, when posting an h-measure value, there is no reason for the h-measure itself to have a URL, so this is an acceptable case to use the nested Microformats object syntax.

The example below creates a new "weight" measurement post as an h-entry with a h-measure objects to describe the weight and bodyfat values.

Example 5
h=entry
&summary=Weighed+155.73+pounds
&weight[type]=h-measure
&weight[properties][num]=155.73
&weight[properties][unit]=lb
&bodyfat[type]=h-measure
&bodyfat[properties][num]=19.83
&bodyfat[properties][unit]=%

Example 6
{
  "type": ["h-entry"],
  "properties": {
    "summary": [
      "Weight 155.73 pounds"
    ],
    "weight": [
      {
        "type": ["h-measure"],
        "properties": {
          "num": ["155.73"],
          "unit": ["lb"]
        }
      }
    ],
    "bodyfat": [
      {
        "type": ["h-measure"],
        "properties": {
          "num": ["19.83"],
          "unit": ["%"]
        }
      }
    ]
  }
}

3.3.4 Unrecognized Properties

If the request includes properties that the server does not recognize, it SHOULD create the post anyway with any values that are recognized, and SHOULD store the unrecognized values internally, and return them when queried.

This allows clients to post rich types of content to servers that recognize it, while also posting fallback content to servers that don't.

3.3.5 Response

When the post is created, the Micropub endpoint MUST return either an HTTP 201 Created status code or HTTP 202 Accepted code, and MUST return a Location header indicating the URL of the created post. [RFC2616]

Example 7
HTTP/1.1 201 Created
Location: https://aaronpk.example/post/1000

If the endpoint chooses to process the request asynchronously rather than creating and storing the post immediately, it MUST return an HTTP 202 Accepted status code, and MUST also return the Location header in this case. If the server is going to return 202, it MUST ensure the object will be created successfully prior to returning 202, as clients will expect the object at the indicated URL to exist at some point in the (near) future. In other words, the server must do any error checking and validation before returning 202.

If the target also provides a shortlink, or if it syndicated the post to another location, the Micropub endpoint MAY return additional URLs using the HTTP Link header, along with an appropriate "rel" value. For example, it can return the short URL of a post by responding with:

Link: <http://aaron.pk/xxxxx>; rel="shortlink"
or can include the location of the syndicated post with:
Link: <https://myfavoritesocialnetwork.example/aaronpk/xxxxxx>; rel="syndication"

Error Response

See the "Error Responses" section below for details on how to indicate an error occurred.

3.4 Update

Micropub servers SHOULD support updating posts, including adding and removing individual properties as described in this section.

Updating entries is done with a JSON post describing the changes to make.

To update an entry, send "action": "update" and specify the URL of the entry that is being updated using the "url" property. The request MUST also include either a replace, add or delete property containing the updates to make.

The values of each property inside the replace, add or delete keys MUST be an array, even if there is only a single value.

3.4.1 Replace

Replace all values of the property. If the property does not exist already, it is created.

Example 8
{
  "action": "update",
  "url": "https://aaronpk.example/post/100",
  "replace": {
    "content": ["hello moon"]
  }
}

This will replace the entire entry content with the new text.

3.4.2 Add

If there are any existing values for this property, they are not changed, the new values are added. If the property does not exist already, it is created.

Adding a syndication URL

Use case: adding a syndication link to a post after it has been published. For example, when a client supports posting first then syndicating to MyFavoriteSocialNetwork or Wikimedia after the fact, the site needs a way to update the original post with the new syndication URL.

To add syndication URLs, include one or more URLs in the update request.

Example 9
{
  "action": "update",
  "url": "https://aaronpk.example/2014/06/01/9/indieweb",
  "add": {
    "syndication": ["http://web.archive.org/web/20040104110725/https://aaronpk.example/2014/06/01/9/indieweb"]
  }
}

Adding Tags

Use case: adding tags to a post after it's been created.

To add multiple values to a property (such as category), provide the new values in an array.

Example 10
{
  "action": "update",
  "url": "https://aaronpk.example/2014/06/01/9/indieweb",
  "add": {
    "category": ["webmention","indieweb"]
  }
}

3.4.3 Remove

If the property exists, remove it. This completely removes the specified property.

Example 11
{
  "action": "update",
  "url": "https://aaronpk.example/2014/06/01/9/indieweb",
  "delete": ["category"]
}

For properties with multiple values, such as categories, you can remove individual entries by value. If no values remain, the property is removed.

Example 12
{
  "action": "update",
  "url": "https://aaronpk.example/2014/06/01/9/indieweb",
  "delete": {
    "category": ["indieweb"]
  }
}

3.4.4 Response

The server MUST respond to successful update requests with HTTP 200, 201 or 204. If the update operation caused the URL of the post to change, the server MUST respond with HTTP 201 and include the new URL in the HTTP Location header. Otherwise, the server MUST respond with 200 or 204, depending on whether the response body has content. No body is required in the response, but the response MAY contain a JSON object describing the changes that were made.

3.5 Delete

Micropub servers SHOULD support deleting posts, and MAY support undeleting posts.

To delete an entire entry at a URL, send a POST request containing action=delete and the URL of the item in the url property.

Example 13
action=delete
&url=https://aaronpk.example/2014/06/01/9/indieweb

Example 14
{
  "action": "delete",
  "url": "https://aaronpk.example/2014/06/01/9/indieweb"
}

To undelete a post, use "undelete" as the action.

Example 15
action=undelete
&url=https://aaronpk.example/2014/06/01/9/indieweb

Example 16
{
  "action": "undelete",
  "url": "https://aaronpk.example/2014/06/01/9/indieweb"
}

3.6 Media Endpoint

In order to provide a better user experience for Micropub applications, as well as to overcome the limitation of being unable to upload a file with the JSON syntax, a Micropub server MAY support a "Media Endpoint". The role of the Media Endpoint is exclusively to handle file uploads and return a URL that can be used in a subsequent Micropub request.

When a Micropub server supports a Media Endpoint, clients can start uploading a photo or other media right away while the user is still creating other parts of the post. The diagram below illustrates a user interface that demonstrates creating a photo post while the photo is uploading asynchronously.

A four-panel diagram of an application illustrating the main view of the application, choosing a photo to upload, uploading the photo to the Media Endpoint while the user enters text, then posting the post contents and photo URL to the Micropub endpoint.

The above user flow applies just as well to mobile apps as it does to desktop apps. In general, the user experience of an application can be improved by having more of the work done asynchronously, giving the user a chance to continue working instead of waiting for the system to finish.

3.6.1 Discovery

To advertise that the Micropub endpoint supports a Media Endpoint, the server MUST include a key called media-endpoint with a value of the full URL of the Media Endpoint in the Micropub configuration request. Clients MUST NOT assume the Media Endpoint is on the same domain as the Micropub endpoint.

Example 17
GET /micropub?q=config
Authorization: Bearer xxxxxxxxx

{
  "media-endpoint": "https://media.example.com/micropub"
}

3.6.2 Authentication

The Media Endpoint MUST accept the same access tokens that the Micropub endpoint accepts.

3.6.3 Request

To upload a file to the Media Endpoint, the client sends a multipart/form-data request with one part named file. The Media Endpoint MAY ignore the suggested filename that the client sends.

Example 18
multipart/form-data; boundary=553d9cee2030456a81931fb708ece92c

--553d9cee2030456a81931fb708ece92c
Content-Disposition: form-data; name="file"; filename="sunset.jpg"
Content-Type: image/jpeg
Content-Transfer-Encoding: binary

... (binary data) ...
--553d9cee2030456a81931fb708ece92c--

Note

The Accessible Platform Architectures Working Group has raised an issue requesting examples of how to include accessibility-related information such as image alt text when creating posts that contain an image. Please see Issue 34 to track the progress of this issue.

3.6.4 Response

The Media Endpoint processes the file upload, storing it in whatever backend it wishes, and generates a URL to the file. The URL SHOULD be unguessable, such as using a UUID in the path. If the request is successful, the endpoint MUST return the URL to the file that was created in the HTTP Location header, and respond with HTTP 201 Created. The response body is left undefined.

Example 19
HTTP/1.1 201 Created
Location: https://media.example.com/file/ff176c461dd111e6b6ba3e1d05defe78.jpg

The Micropub client can then use this URL as the value of e.g. the "photo" property of a Micropub request.

The Media Endpoint MAY periodically delete files uploaded if they are not used in a Micropub request within a specific amount of time.

3.7 Querying

Micropub clients may need to query the Micropub endpoint to discover its capabilities, such as finding a list of syndication targets that it displays to the user, or retrieving the source of a post to display in the updating interface.

To query, make a GET request to the Micropub endpoint and use the q parameter to specify what you are querying.

Note

The Micropub endpoint may include a query string such as ?micropub=endpoint, so in this case, Micropub clients MUST append the q parameter instead of replacing the query string.

3.7.1 Configuration

When a user initially logs in to a Micropub client, the client will want to query some initial information about the user's endpoint. The client SHOULD make a query request q=config to obtain initial configuration information.

The server SHOULD include the following information in the configuration response.

  • The list of syndication endpoints supported (see Syndication Targets for details)
  • The Media Endpoint if supported

Example 20
GET /micropub?q=config
Authorization: Bearer xxxxxxxxx

{
  "media-endpoint": "https://media.example.com/micropub",
  "syndicate-to": [
    {
      "uid": "https://myfavoritesocialnetwork.example/aaronpk",
      "name": "aaronpk on myfavoritesocialnetwork",
      "service": {
        "name": "My Favorite Social Network",
        "url": "https://myfavoritesocialnetwork.example/",
        "photo": "https://myfavoritesocialnetwork.example/img/icon.png"
      },
      "user": {
        "name": "aaronpk",
        "url": "https://myfavoritesocialnetwork.example/aaronpk",
        "photo": "https://myfavoritesocialnetwork.example/aaronpk/photo.jpg"
      }
    }
  ]
}

3.7.2 Source Content

A Micropub client can query the endpoint to return specific properties of a post. This allows a client to request only the properties it needs or knows about, supporting such uses as making an interface to add tags to a post.

To query, make a GET request to the Micropub endpoint and set the q parameter to source, and include the URL of the post in the url parameter. The query can specify the list of properties being requested by setting one or more values for the properties key. If more than one is specified, use array bracket notation for each name, according to [HTML5] URL encoding.

The endpoint MUST return the response in [microformats2-parsing] [JSON] format, with an object named properties, where the keys are the names of the properties requested. If no properties are specified, then the response MUST include all properties, as well as a type property indicating the vocabulary of the post.

Example 21
GET /micropub?q=source&properties[]=published&properties[]=category&url=https://aaronpk.example/post/1000
Authorization: Bearer xxxxxxxxx

{
  "properties": {
    "published": ["2016-02-21T12:50:53-08:00"],
    "category": [
      "foo", 
      "bar"
    ]
  }
}

Example 22
GET /micropub?q=source&url=https://aaronpk.example/post/1000
Authorization: Bearer xxxxxxxxx

{
  "type": "h-entry",
  "properties": {
    "published": ["2016-02-21T12:50:53-08:00"],
    "content": ["Hello World"],
    "category": [
      "foo", 
      "bar"
    ]
  }
}

HTML Content

If the source of the post was written as HTML content, then the endpoint MUST return the content property as an object containing an html property. Otherwise, the endpoint MUST return a string value for the content property, and the client will treat the value as plain text. This matches the behavior of the values of properties in [microformats2-parsing].

Below is an example of requesting the content of a post which was authored as HTML.

Example 23
GET /micropub?q=source&properties=content&url=https://aaronpk.example/post/1000
Authorization: Bearer xxxxxxxxx

{
  "properties": {
    "content": [
      {
        "html": "<b>Hello</b> <i>World</i>"
      }
    ]
  }
}

3.7.3 Syndication Targets

To return a list of supported syndication targets, set the q parameter to syndicate-to.

GET /micropub?q=syndicate-to

The endpoint MUST return the response in [JSON] format, with a key of syndicate-to and the values being objects descriptive of the supported syndication targets.

Example 24
GET /micropub?q=syndicate-to
Authorization: Bearer xxxxxxxxx
Accept: application/json

HTTP/1.1 200 OK
Content-type: application/json

{
  "syndicate-to": [
    {
      "uid": "https://archive.org/",
      "name": "archive.org"
    },
    {
      "uid": "https://wikimedia.org/",
      "name": "WikiMedia"
    },
    {
      "uid": "https://myfavoritesocialnetwork.example/aaronpk",
      "name": "aaronpk on myfavoritesocialnetwork",
      "service": {
        "name": "My Favorite Social Network",
        "url": "https://myfavoritesocialnetwork.example/",
        "photo": "https://myfavoritesocialnetwork.example/img/icon.png"
      },
      "user": {
        "name": "aaronpk",
        "url": "https://myfavoritesocialnetwork.example/aaronpk",
        "photo": "https://myfavoritesocialnetwork.example/aaronpk/photo.jpg"
      }
    }
  ]
}

At a minimum, a syndication destination MUST have uid and name properties. The uid property is opaque to the client, and is the value the client sends in the Micropub request to indicate the targets to syndicate to. The name property is the value the client can display to the user. The name should be unambiguously descriptive of the destination, so that if for example there are two destinations on the same service, the name can disambiguate them.

The Micropub server MAY also include additional information about the destination service and user account. This is accomplished with the additional properties service and user, both of which can have three properties, name (a human-readable name), url and photo (both URLs).

The client may use the service and user properties to enhance the display of the syndication options, for example by including the user or service photos on the syndication buttons.

3.8 Error Response

If there was an error with the request, the endpoint MUST return an appropriate HTTP status code, typically 400, 401, or 403, and MAY include a description of the error. If an error body is returned, the response body MUST be encoded as a [JSON] object and include at least a single property named error with the value set to one of the below:

The response body MAY also contain an error_description property with a human-readable description of the error message, used to assist the client developer in understanding the error. This is not meant to be shown to the end user.

See the OAuth 2 Bearer Token [RFC6750] spec for more details on the how to return error responses.

Example 25
GET /micropub?q=source&url=https://aaronpk.example/post/404
Authorization: Bearer xxxxxxxx

HTTP/1.1 400 Bad Request
Content-type: application/json

{
  "error": "not_found",
  "error_description": "The post with the requested URL was not found"
}

4. Vocabulary

The vocabularies used in Micropub requests SHOULD be the vocabularies defined by [Microformats2] version 2. If the Microformats2 vocabulary is used, clients and servers MUST support at least the [h-entry] vocabulary. Other vocabularies with widespread usage include [h-event] and [h-card]. When creating objects, the vocabulary of the object is indicated in the parameter h, or type in the JSON syntax. If no type is provided, the server SHOULD assume a default value of entry.

4.1 Examples of Creating Objects

This section is non-normative.

To indicate the object being created, use a property called h, (which would never be the name of a property of a Microformats object), followed by the name of the Microformats object. Examples:

The following properties may be included in a request to create a new [h-entry]:

4.1.1 New Note

Posting a new note with tags, syndicating to myfavoritesocialnetwork:

  • content
  • category
  • published (optional, defaults to "now" if not present. Useful for writing offline and syncing later.)
  • mp-syndicate-to

Example 26
POST /micropub HTTP/1.1
Host: aaronpk.example
Authorization: Bearer XXXXXXXXXXX
Content-type: application/x-www-form-urlencoded

h=entry
&content=My+favorite+of+the+%23quantifiedself+trackers%2C+finally+released+their+official+API
&category[]=quantifiedself&category[]=api
&mp-syndicate-to=https://myfavoritesocialnetwork.example/aaronpk

Minimal Example

Example 27
POST /micropub HTTP/1.1
Host: aaronpk.example
Content-type: application/x-www-form-urlencoded
Authorization: Bearer XXXXXXX

h=entry
&content=Hello+World

Example 28
curl https://aaronpk.example/micropub -d h=entry -d "content=Hello World" -H "Authorization: Bearer XXXXXXX"

4.1.2 New Reply

Posting a new note with tags, syndicating to myfavoritesocialnetwork:

  • content
  • in-reply-to
  • published
  • mp-syndicate-to

Example 29
POST /micropub HTTP/1.1
Host: aaronpk.example
Authorization: Bearer XXXXXXXXXXX
Content-type: application/x-www-form-urlencoded

h=entry
&content=%40BarnabyWalters+My+favorite+for+that+use+case+is+Redis.
&in-reply-to=https://waterpigs.example/notes/4S0LMw/
&mp-syndicate-to=https://myfavoritesocialnetwork.example/aaronpk

4.1.3 New Article

Posting a new article with HTML content. Note that in this case, the content property is actually sent as an object containing the key html. This corresponds with the Microformats 2 syntax for indicating the parsed value contains HTML.

  • name
  • content[html]
  • category
  • published

Example 30
POST /micropub HTTP/1.1
Host: aaronpk.example
Content-type: application/x-www-form-urlencoded

h=entry
&name=Itching%3A+h-event+to+iCal+converter
&content[html]=Now+that+I%27ve+been+%3Ca+href%3D%22http%3A%2F%2Faaronparecki.com%22%3Ecreating+a+list+of+events%3C%2Fa%3E
+on+my+site+it+would+be+great+if+I+could+get+a+more+calendar-like+view+of+that+list...
&category[]=indieweb&category[]=hevent&category[]=events
&category[]=calendar&category[]=p3k

4.1.4 Adding Files

When a Micropub request includes a file, the entire request is sent in multipart form-data encoding, and the file is named according to the property it corresponds with in the vocabulary, either audio, video or photo. A request MAY include one or more of these files.

For example, a service may post a video in the video property as well as a single frame preview of the video in the photo property.

In PHP, these files are accessible using the $_FILES array:

$_FILES['video']
$_FILES['photo']
$_FILES['audio']

Note that there is no way to upload a file when the request body is JSON encoded. Instead, you can first send the photo to the Media Endpoint and then use the resulting URL in the JSON post.

The Micropub endpoint may store the file directly, or make an external request to upload it to a different backend storage, such as Amazon S3.

5. Authentication and Authorization

5.1 Authentication

Micropub requests MUST be authenticated by including a Bearer Token in either the HTTP header or a form-encoded body parameter as described in the OAuth Bearer Token RFC. [RFC6750] Micropub servers MUST accept the token using both methods.

HTTP Header

Authorization: Bearer XXXXXXXXX

Form-Encoded Body Parameter

access_token=XXXXXXXXX

5.2 Authorization

An app that wants to post to a user's Micropub endpoint will need to obtain authorization from the user in order to get an access token. Authorization SHOULD be handled via the OAuth 2.0 [RFC6749] protocol, including the [IndieAuth] extension which supports endpoint discovery from a URL. See Obtaining an Access Token for more details.

5.3 Endpoint Discovery

Micropub defines a link relation value of micropub to link to a website's Micropub endpoint from the profile page identifying the user.

A Micropub client SHOULD be able to be configured by authenticating with a domain name using [IndieAuth]. During this authentication (and authorization), the client discovers the Micropub endpoint which will be used to create posts, as well as obtains an access token it will use in the Micropub requests.

The client looks for a <link rel="micropub"> tag in the HTML head of the URL used to authenticate, or sends an HTTP Link header with a rel value of micropub.

Link: <https://aaronpk.example/micropub>; rel="micropub"

<link rel="micropub" href="https://aaronpk.example/micropub">

5.4 Scope

The Micropub server MUST require the bearer token to include at least one scope value, in order to ensure posts cannot be created by arbitrary tokens.

The client may request one or more scopes during the authorization request. It does this according to standard OAuth 2.0 techniques, by passing a space-separated list of scope names in the authorization request. [RFC6749]

The authorization server MUST indicate to the user any scopes that are part of the request, whether or not the authorization server recognizes the scopes. The authorization server MAY also allow the user to add or remove scopes that the client requests.

Most Micropub servers require clients to obtain the "create" scope in order to create posts. However, some servers MAY require more granular scope, such as "delete", "update", or "create:video", in order to limit the abilities of various clients. See Scope for more details and a list of all currently used values for scope.

6. IANA Considerations

The link relation type below has been registered by IANA per Section 6.2.1 of [RFC5988]:

Relation Name:
micropub
Description:
Used for discovery of a Micropub endpoint which can be used to create posts according to the Micropub protocol.
Reference:
W3C Micropub Specification (https://www.w3.org/TR/micropub/)

A. Resources

This section is non-normative.

A.1 Implementations

This section is non-normative.

You can find a list of Micropub implementations on micropub.net

B. Acknowledgements

The editor wishes to thank the IndieWeb community and other implementers for their support, encouragement and enthusiasm.

C. Change Log

This section is non-normative.

C.1 Changes from 21 June 2016 WD to this version

C.2 Changes from 04 May 2016 WD to 21 June 2016 WD

C.3 Changes from 01 March 2016 WD to 04 May 2016 version

This section lists changes from the 01 March 2016 FPWD to this Working Draft

C.4 Changes from 28 January 2016 FPWD to 01 March 2016 version

This section lists changes from the 28 January 2016 FPWD to this Working Draft

D. References

D.1 Normative references

[HTML5]
Ian Hickson; Robin Berjon; Steve Faulkner; Travis Leithead; Erika Doyle Navara; Edward O'Connor; Silvia Pfeiffer. W3C. HTML5. 28 October 2014. W3C Recommendation. URL: https://www.w3.org/TR/html5/
[JSON]
D. Crockford. IETF. The application/json Media Type for JavaScript Object Notation (JSON). July 2006. Informational. URL: https://tools.ietf.org/html/rfc4627
[RFC2119]
S. Bradner. IETF. Key words for use in RFCs to Indicate Requirement Levels. March 1997. Best Current Practice. URL: https://tools.ietf.org/html/rfc2119
[RFC2616]
R. Fielding; J. Gettys; J. Mogul; H. Frystyk; L. Masinter; P. Leach; T. Berners-Lee. IETF. Hypertext Transfer Protocol -- HTTP/1.1. June 1999. Draft Standard. URL: https://tools.ietf.org/html/rfc2616
[RFC5988]
M. Nottingham. IETF. Web Linking. October 2010. Proposed Standard. URL: https://tools.ietf.org/html/rfc5988
[RFC6749]
D. Hardt, Ed.. IETF. The OAuth 2.0 Authorization Framework. October 2012. Proposed Standard. URL: https://tools.ietf.org/html/rfc6749
[RFC6750]
M. Jones; D. Hardt. IETF. The OAuth 2.0 Authorization Framework: Bearer Token Usage. October 2012. Proposed Standard. URL: https://tools.ietf.org/html/rfc6750
[h-entry]
Tantek Çelik. microformats.org. h-entry. Living Specification. URL: http://microformats.org/wiki/h-entry
[microformats2-parsing]
Tantek Çelik. microformats.org. Microformats2 Parsing. Living Specification. URL: http://microformats.org/wiki/microformats2-parsing

D.2 Informative references

[IndieAuth]
Aaron Parecki. indieweb.org. IndieAuth. Living Specification. URL: https://indieweb.org/IndieAuth-spec
[Microformats2]
Tantek Çelik. microformats.org. Microformats 2. Living Specification. URL: http://microformats.org/wiki/microformats2
[RFC5870]
A. Mayrhofer; C. Spanring. IETF. A Uniform Resource Identifier for Geographic Locations ('geo' URI). June 2010. Proposed Standard. URL: https://tools.ietf.org/html/rfc5870
[h-adr]
Tantek Çelik. microformats.org. h-adr. Living Specification. URL: http://microformats.org/wiki/h-adr
[h-card]
Tantek Çelik. microformats.org. h-card. Living Specification. URL: http://microformats.org/wiki/h-card
[h-event]
Tantek Çelik. microformats.org. h-event. Living Specification. URL: http://microformats.org/wiki/h-event