Status of This Document

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

3. Syntax

As [Microformats2] 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 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.

  • access_token - the OAuth Bearer token authenticating the request (the access token may be sent in an HTTP Authorization header or this form parameter)
  • h - used to specify the object type being created
  • q - used to query a Micropub endpoint
  • url - indicates the URL of the object being changed
  • mp-action - indicates whether this is an update, delete, or undelete
  • replace - for updates, the top-level property containing properties to replace
  • add - for updates, the top-level property containing properties to add
  • delete - for updates, the top-level property containing properties to remove
  • mp-* - reserved for future use

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, 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=53d9cee2030456a81931fb708ece92c

--53d9cee2030456a81931fb708ece92c
Content-Disposition: form-data; name="h"

entry
--53d9cee2030456a81931fb708ece92c
Content-Disposition: form-data; name="content"

Hello World
--53d9cee2030456a81931fb708ece92c
Content-Disposition: form-data; name="photo"; filename="aaronpk.png"
Content-Type: image/png
Content-Transfer-Encoding: binary

... (binary data) ...
--53d9cee2030456a81931fb708ece92c--

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

See the Media Endpoint section for more information.

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]

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

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.

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 "mp-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 7

{
  "mp-action": "update",
  "url": "http://example.com/post/1",
  "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 8

{
  "mp-action": "update",
  "url": "http://aaronparecki.com/notes/2014/06/01/2/indieweb",
  "add": {
    "syndication": ["https://archive.org/"]
  }
}

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 9

{
  "mp-action": "update",
  "url": "http://aaronpk.example/notes/2014/06/01/2/indieweb",
  "add": {
    "category": ["webmention","indieweb"]
  }
}

3.4.3 Remove

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

Example 10

{
  "mp-action": "update",
  "url": "http://example.com/post/1",
  "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 11

{
  "mp-action": "update",
  "url": "http://example.com/post/1",
  "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 mp-action=delete and the URL of the item in the url property.

Example 12

mp-action=delete
&url=http://example.com/post/1

Example 13

{
  "mp-action": "delete",
  "url": "http://example.com/post/1"
}

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

Example 14

mp-action=undelete
&url=http:

Example 15

{
  "mp-action": "undelete",
  "url": "http://example.com/post/1"
}

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 19

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] [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 20

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

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

Example 21

GET /micropub?q=source&url=http://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].

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

Example 22

GET /micropub?q=source&properties=content&url=http://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 23

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:

  • HTTP 403: forbidden - The authenticated user does not have permission to perform this request
  • HTTP 401: insufficient_scope - The scope of this token does not meet the requirements for this request. The client may wish to re-authorize the user to obtain the necessary scope. The response MAY include the "scope" attribute with the scope necessary to successfully perform this request.
  • HTTP 400: invalid_request - The request is missing a required parameter, or there was a problem with a value of one of the parameters
  • HTTP 400: not_found - The post with the requested URL was not found

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 24

GET /micropub?q=source&url=http://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"
}

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.

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:

HTML Link Tag

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