HTTP commands are sent as CGI requests having the following form:

{{{
GET /hgweb.cgi?cmd=foo&param1=bar HTTP/1.1
}}}

Results are returned with the Content-Type application/mercurial-0.1.

The best way to explore the protocol is to run `hg serve` in a terminal, then try out the various commands. Errors, such as missing parameters, will be logged in the terminal window, including source references.

= Available commands =

The available commands can be seen marked with `@wireprotocommand` in [[Source:mercurial/wireprotov1server.py]], along with arguments.

=== lookup ===

Given a changeset reference (given by the `key` parameter), yields the [[ChangeSetID|changeset ID]].

Returns a status code (1 on success, 0 on failure) and a result (the changeset ID or error message).

Examples:
{{{
$ curl 'https://www.mercurial-scm.org/repo/hello?cmd=lookup&key=0'
1 0a04b987be5ae354b710cefeba0e2d9de7ad41a9

$ curl 'https://www.mercurial-scm.org/repo/hello?cmd=lookup&key=33d290cc14ae48c8c18d2a2c9dfae99728ee0cff'
0 unknown revision '33d290cc14ae48c8c18d2a2c9dfae99728ee0cff'

$ curl 'https://www.mercurial-scm.org/repo/hello?cmd=lookup&key=tip'
1 82e55d328c8ca4ee16520036c0aaace03a5beb65
}}}

=== heads ===

Returns a space separated list of [[ChangeSetID|changeset ID]] identifying all the heads in the repository. Takes no parameters

=== branches ===

=== changegroup ===
=== changegroupsubset ===
=== between ===
=== capabilities ===
Accepts no parameters. Returns a whitespace-separated list of other commands accepted by this server.
For the ''unbundle'' command, produces the form unbundle=HG10GZ,HG10BZ,HG10UN if all three compression
schemes are supported.
=== unbundle ===
Usage:
{{{
POST /hgweb.cgi?cmd=unbundle&heads=HEADS HTTP/1.1
content-type: application/octet-stream
}}}  

This command allows for the upload of new changes to the repository. The body of the POST request must be
a changegroup in BundleFormat. The returned output is the same as what the ''hg unbundle'' command would print to standard output if it was being run locally.

=== stream_out ===
----
CategoryInternals