2.1 Basic Concepts, Arguments and Variables

Originally Ghub supported only Github but now it also supports Gitlab, Gitea, Gogs and Bitbucket. For the historic reason just given, the function ghub-request defaults to acting on a github forge, but can be told to act on another forge using the FORGE argument.

The FORGE argument only specifies what kind of forge to act on, not which instance. The HOST argument can be used to select the instance. For some forges a default instance is defined:

• Forge github defaults to host api.github.com.
• Forge gitlab defaults to host gitlab.com/api/v4.
• Forge bitbucket defaults to host api.bitbucket.org/2.0.
• No canonical host exists for the gitea and gogs forges and localhost:3000/api/v1 is used as the default host in both cases.

Together the FORGE and HOST arguments specify the forge type and instance. In addition to that, it is also necessary to specify on whose behalf the request is being made, which can be done using the USERNAME and AUTH arguments. For example:

(ghub-request "GET" "/user" nil
              :forge 'github
              :host "api.github.com"
              :username "tarsius"
              :auth 'forge)

Having to specify these arguments for every request is inconvenient. Additional variables and convenience functions can be used to make that unnecessary in most cases.

(But for debugging purposes the above explicit form is very useful. You will obviously have to change the value of USERNAME and you should use ghub as AUTH when first trying this at home.)

These variables can be set globally and/or for a specific repository.

• For "api.github.com" (aka the API of https://github.com) the Git variable github.user specifies the user.
• For another github instance the Git variable github.HOST.user specifies the user. The HOST in that variable name is the same as the value of the HOST argument of the called function.
• Instead of specifying the HOST in every function call, the Git variable github.host can be used. This should only be set locally.

These github specific variables are discussed in more detail in Github Configuration Variables.

For gitlab and bitbucket forges similar variables are available:

• gitlab.user specifies the https://gitlab.com user.
• gitlab.HOST.user specifies the user for the HOST gitlab instance.
• gitlab.host specifies the gitlab host, unless the HOST argument is non-nil
• bitbucket.user specifies the https://bitbucket.org user.
• bitbucket.HOST.user specifies the user for the HOST bitbucket instance.
• bitbucket.host specifies the bitbucket host, unless the HOST argument is non-nil.

For the gitea and gogs forges some similar variables are available, however for some of the ghub.* variables no equivalent variable exist for these two forges:

• gitea.user is not used because no canonical gitea instance exists.
• gitea.HOST.user specifies the user for the HOST gitea instance.
• gitea.host specifies the gitea host, unless the HOST argument is non-nil
• gogs.user is not used because no canonical gogs instance exists.
• gogs.HOST.user specifies the user for the HOST gogs instance.
• gogs.host specifies the gogs host, unless the HOST argument is non-nil

2.2 Setting the Username

Ghub needs to know your username that you use on the host that you want it to connect to. For each host a different Git variable has to be set to specify the username on that host. More than one variable is needed because you might use different usernames on different hosts.

Setting your Github.com Username

To inform Ghub about your "github.com" username do this:

git config --global github.user USERNAME

If you need to identify as another user in a particular repository, then you have to set that variable locally:

cd /path/to/repo
git config --local github.user USERNAME

Setting your Gitlab.com Username

To inform Ghub about your "gitlab.com" username do this:

git config --global gitlab.user USERNAME

If you need to identify as another user in a particular repository, then you have to set that variable locally:

cd /path/to/repo
git config --local gitlab.user USERNAME

Make sure you use the correct USERNAME for this forge/host. It might not be the same as on "github.com"!

Setting your Github Enterprise Username

For Github Enterprise instances you have to specify where the API can be accessed and a different variable has to be used to set the username.

For example if the API is available at https://example.com/api/v3, then you should do this:

git config --global github.example.com/api/v3.user USERNAME

Make sure you use the correct USERNAME for this instance. It might not be the same as on "github.com"!

Doing this only tells Ghub who you are on this host, additionally you have to tell Ghub which repositories are connected to that forge/host, like so:

cd /path/to/repo
git config --local github.host example.com/api/v3

Setting your Username for Other Hosts and/or Forges

To inform Ghub about your username on HOST (a FORGE instance) do this:

git config --global FORGE.HOST.user USERNAME

FORGE can be one of bitbucket, gitea or gogs. It can also be github or gitlab; but if that is the case, then you should look at the preceding sections instead, which discuss these cases specifically.

HOST identifies the instance. This actually points at the top-level endpoint of the API and may contain path components, e.g.: example.com/api.

If you need to identify as another user in a particular repository, then you have to set that variable locally:

cd /path/to/repo
git config --local FORGE.HOST.user USERNAME

2.3 Creating and Storing a Token

• Creating a Token
• Storing a Token

(setq auth-sources '("~/.authinfo"))

(setq auth-sources '("~/.authinfo.gpg"))

machine api.github.com login ziggy^forge password 012345abcdef...

machine gitlab.com/api/v4 login ziggy^forge password 012345abcdef...

2.4 Github Configuration Variables

The username and, unless you only use Github.com itself, the Github Enterprise instance have to be configured using Git variables. In rare cases it might also be necessary to specify the identity of the local machine, which is done using a lisp variable.

Variable: github.user ¶

The Github.com username. This should be set globally and if you have multiple Github.com user accounts, then you should set this locally only for those repositories that you want to access using the secondary identity.

Variable: github.HOST.user ¶

This variable serves the same purpose as github.user but for the Github Enterprise instance identified by HOST.

The reason why separate variables are used is that this makes it possible to set both values globally instead of having to set one of the values locally in each and every repository that is connected to the Github Enterprise instance, not Github.com.

Variable: github.host ¶

This variable should only be set locally for a repository and specifies the Github Enterprise edition that that repository is connected to. You should not set this globally because then each and every repository becomes connected to the specified Github Enterprise instance, including those that should actually be connected to Github.com.

When this is undefined, then "api.github.com" is used (defined in the constant ghub-default-host, which you should never attempt to change.)

3.1 Their APIs

Of course this manual does not cover the APIs of all forges that it supports, but for your convenience, here are the links to their API manuals:

• Github:
  • https://developer.github.com/v4 (GraphQl)
  • https://developer.github.com/v3 (REST)
• Gitlab:
  • https://docs.gitlab.com/ee/api/README.html
• Gitea:
  • https://docs.gitea.io/en-us/api-usage
  • https://try.gitea.io/api/swagger
• Gogs:
  • https://github.com/gogs/go-gogs-client/wiki
• Bitbucket:
  • https://developer.atlassian.com/bitbucket/api/2/reference

3.2 Making REST Requests

Function: ghub-request method resource &optional params &key query payload headers unpaginate noerror reader username auth host callback errorback url value error extra method* ¶

This function makes a request for RESOURCE using METHOD. PARAMS, QUERY, PAYLOAD and/or HEADERS are alists holding additional request data. The response body is returned and the response headers are stored in the variable ghub-response-headers.

• METHOD is the HTTP method, given as a string.
• RESOURCE is the resource to access, given as a string beginning with a slash.
• PARAMS, QUERY, PAYLOAD and HEADERS are alists and are used to specify request data. All these arguments are alists that resemble the JSON expected and returned by the Github API. The keys are symbols and the values stored in the cdr (not the cadr) can be strings, integers, or lists of strings and integers.

  The Github API documentation is vague on how data has to be transmitted and for a particular resource usually just talks about "parameters". Generally speaking when the METHOD is "HEAD" or "GET", then they have to be transmitted as a query, otherwise as a payload.

  • Use PARAMS to automatically transmit like QUERY or PAYLOAD would depending on METHOD.
  • Use QUERY to explicitly transmit data as a query.
  • Use PAYLOAD to explicitly transmit data as a payload. Instead of an alist, PAYLOAD may also be a string, in which case it gets encoded as UTF-8 but is otherwise transmitted as-is.
  • Use HEADERS for those rare resources that require that the data is transmitted as headers instead of as a query or payload. When that is the case, then the Github API documentation usually mentions it explicitly.
• If SILENT is non-nil, then progress reports and the like are not messaged.
• If UNPAGINATE is t, then this function makes as many requests as necessary to get all values. If UNPAGINATE is a natural number, then it gets at most that many pages. For any other non-nil value it raises an error.
• If NOERROR is non-nil, then no error is raised if the request fails and nil is returned instead. If NOERROR is return, then the error payload is returned instead of nil.
• If READER is non-nil, then it is used to read and return from the response buffer. The default is ghub--read-json-payload. For the very few resources that do not return JSON, you might want to use ghub--decode-payload.
• If USERNAME is non-nil, then the request is made on behalf of that user. It is better to specify the user using the Git variable github.user for "api.github.com", or github.HOST.user if connecting to a Github Enterprise instance.
• Each package that uses Ghub should use its own token. If AUTH is nil or unspecified, then the generic ghub token is used instead. This is only acceptable for personal utilities. A package that is distributed to other users should always use this argument to identify itself, using a symbol matching its name.

  Package authors who find this inconvenient should write a wrapper around this function and possibly for the method-specific functions as well.

  Beside nil, some other symbols have a special meaning too. none means to make an unauthorized request. basic means to make a password based request. If the value is a string, then it is assumed to be a valid token. basic and an explicit token string are only intended for internal and debugging uses.

  If AUTH is a package symbol, then the scopes are specified using the variable AUTH-github-token-scopes. It is an error if that is not specified. See ghub-github-token-scopes for an example.

• If HOST is non-nil, then connect to that Github instance. This defaults to "api.github.com". When a repository is connected to a Github Enterprise instance, then it is better to specify that using the Git variable github.host instead of using this argument.
• If FORGE is gitlab, then connect to Gitlab.com or, depending on HOST, to another Gitlab instance. This is only intended for internal use. Instead of using this argument you should use function glab-request and other glab-* functions.
• If CALLBACK and/or ERRORBACK is non-nil, then this function makes one or more asynchronous requests and calls CALLBACK or ERRORBACK when finished. If no error occurred, then it calls CALLBACK, unless that is nil.

  If an error occurred, then it calls ERRORBACK, or if that is nil, then CALLBACK. ERRORBACK can also be t, in which case it signals instead. NOERROR is ignored for all asynchronous requests.

  Both callbacks are called with four arguments.

  1. For CALLBACK, the combined value of the retrieved pages. For ERRORBACK, the error that occurred when retrieving the last page.
  2. The headers of the last page as an alist.
  3. Status information provided by url-retrieve. Its :error property holds the same information as the first argument to ERRORBACK.
  4. A ghub--req struct, which can be passed to ghub-continue (which see) to retrieve the next page, if any.

Function: ghub-continue args ¶

If there is a next page, then this function retrieves that.

This function is only intended to be called from callbacks. If there is a next page, then that is retrieved and the buffer that the result will be loaded into is returned, or t if the process has already completed. If there is no next page, then return nil.

Callbacks are called with four arguments (see ghub-request). The forth argument is a ghub--req struct, intended to be passed to this function. A callback may use the struct’s extra slot to pass additional information to the callback that will be called after the next request. Use the function ghub-req-extra to get and set the value of that slot.

As an example, using ghub-continue in a callback like so:

(ghub-get "/users/tarsius/repos" nil
          :callback (lambda (value _headers _status req)
                      (unless (ghub-continue req)
                        (setq my-value value))))

is equivalent to:

(ghub-get "/users/tarsius/repos" nil
          :unpaginate t
          :callback (lambda (value _headers _status _req)
                      (setq my-value value)))

To demonstrate how to pass information from one callback to the next, here we record when we start fetching each page:

(ghub-get "/users/tarsius/repos" nil
          :extra (list (current-time))
          :callback (lambda (value _headers _status req)
                      (push (current-time) (ghub-req-extra req))
                      (unless (ghub-continue req)
                        (setq my-times (ghub-req-extra req))
                        (setq my-value value))))

Variable: ghub-response-headers ¶

A select few Github API resources respond by transmitting data in the response header instead of in the response body. Because there are so few of these inconsistencies, ghub-request always returns the response body.

To access the response headers use this variable after ghub-request has returned.

Function: ghub-response-link-relations req headers payload ¶

This function returns an alist of the link relations in HEADERS, or if optional HEADERS is nil, then those in ghub-response-headers.

When accessing a Bitbucket instance then the link relations are in PAYLOAD instead of HEADERS, making their API merely RESTish and forcing this function to append those relations to the value of ghub-response-headers, for later use when this function is called with nil for PAYLOAD.

3.3 Making GraphQL Requests

Function: ghub-graphql graphql &optional variables &key username auth host callback silent callback errorback value extra ¶

This function makes a GraphQL request using GRAPHQL and VARIABLES as inputs. GRAPHQL is a GraphQL string. VARIABLES is a JSON-like alist. The other arguments behave as for ghub-request (which see).

The response is returned as a JSON-like alist. Even if the response contains errors, this function does not raise an error. Cursor-handling is likewise left to the caller.

ghub-graphql is a thin convenience wrapper around ghub-request, similar to ghub-post and friends. While the latter only hard-code the value of the METHOD argument, the former also hard-codes RESOURCE and constructs PAYLOAD from GRAPHQL and VARIABLES. It also drops UNPAGINATE, NOERROR, READER (internal functions expect alist-ified JSON) and FORGE (only Github currently supports GraphQL).

ghub-graphql does not account for the fact that pagination works differently in GraphQL than it does in REST, so users of this function have to deal with that themselves. Likewise error handling works differently and has to be done by the caller too.

An early attempt at implementing automatic unpaginating for GraphQL can be found in the faithful-graphql branch, provided I haven’t deleted that by now. On that branch I try to do things as intended by the designers of GraphQL, using variables and fragments, and drowning in a sea of boilerplate.

The problem with that approach is that it only works for applications that fetch specific information on demand and actually want things to be paginated. I am convinced that GraphQL is very nice for web apps.

However the Forge package for which I have implemented all of this has very different needs. It wants to fetch "all the data" and "cache" it locally, so that it is available even when there is no internet connection. GraphQL was designed around the idea that you should be able to "ask for what you need and get exactly that". But when that boils down to "look, if I persist, then you are going to hand me over all the data anyway, so just caught it up already", then things start to fall apart. If Github’s GraphQL allowed pagination to be turned off completely, then teaching ghub-graphql about error handling would be enough.

But it doesn’t and when doing things as intended, then that leads to huge amounts of repetitive boilerplate, which is so boring to write that doing it without introducing bugs left and right is near impossible; so I decided to give up on GraphQL variables, fragments and conditions, and instead implement something more powerful, though also more opinionated.

Function: ghub--graphql-vacuum query variables callback &optional until &key narrow username auth host forge ¶

This function is an opinionated alternative to ghub-graphql. It relies on dark magic to get the job done.

It makes an initial request using QUERY. It then looks for paginated edges in the returned data and makes more requests to resolve them. In order to do so it automatically transforms the initial QUERY into another query suitable for that particular edge. The data retrieved by subsequent requests is then injected into the data of the original request before that is returned or passed to the callback. If subsequently retrieved data features new paginated edges, then those are followed recursively.

The end result is essentially the same as using ghub-graphql, if only it were possible to say "do not paginate anything". The implementation is much more complicated because it is not possible to do that.

QUERY is a GraphQL query expressed as an s-expression. The bundled gsexp library is used to turn that into a GraphQL query string. Only a subset of the GraphQL features are supported; fragments for example are not, and magical stuff happens to variables. This is not documented yet, I am afraid. Look at existing callers.

VARIABLES is a JSON-like alist as for ghub-graphql.

UNTIL is an alist ((EDGE-until . VALUE)...). When unpaginating EDGE try not to fetch beyond the element whose first field has the value VALUE and remove that element as well as all "lesser" elements from the retrieved data if necessary. Look at forge--pull-repository for an example. This is only useful if you "cache" the response locally and want to avoid fetching data again that you already have.

Other arguments behave as for ghub-graphql and ghub-request, more or less. If CALLBACK is nil, pretty-print the response.

Using ghub--graphql-vacuum, the following resource specific functions are implemented. These functions are not part of the public API yet and are very much subject to change.

Function: ghub-fetch-repository owner name callback &optional until &key username auth host forge ¶

This function asynchronously fetches forge data about the specified repository. Once all data has been collected, CALLBACK is called with the data as the only argument.

Function: ghub-fetch-issue owner name callback &optional until &key username auth host forge ¶

This function asynchronously fetches forge data about the specified issue. Once all data has been collected, CALLBACK is called with the data as the only argument.

Function: ghub-fetch-pullreq owner name callback &optional until &key username auth host forge ¶

This function asynchronously fetches forge data about the specified pull-request. Once all data has been collected, CALLBACK is called with the data as the only argument.

Note that in order to avoid duplication all of these functions base their initial query on the query stored in ghub-fetch-repository. The latter two pass that query through ghub--graphql-prepare-query, which then uses ghub--graphql-narrow-query to remove parts the caller is not interested in. These two functions are also used internally, when unpaginating, but as demonstrated here they can be useful even before making an initial request.

3.4 Github Convenience Wrappers

Function: ghub-head resource &optional params &key query payload headers unpaginate noerror reader username auth host callback errorback ¶

Function: ghub-get resource &optional params &key query payload headers unpaginate noerror reader username auth host callback errorback ¶

These functions are simple wrappers around ghub-request. Their signature is identical to that of the latter, except that they do not have an argument named METHOD. The HTTP method is instead given by the second word in the function name.

As described in the documentation for ghub-request, it depends on the used method whether the value of the PARAMS argument is used as the query or the payload. For the "HEAD" and "GET" methods it is used as the query.

Function: ghub-put resource &optional params &key query payload headers unpaginate noerror reader username auth host callback errorback ¶

Function: ghub-post resource &optional params &key query payload headers unpaginate noerror reader username auth host callback errorback ¶

Function: ghub-patch resource &optional params &key query payload headers unpaginate noerror reader username auth host callback errorback ¶

Function: ghub-delete resource &optional params &key query payload headers unpaginate noerror reader username auth host callback errorback ¶

These functions are simple wrappers around ghub-request. Their signature is identical to that of the latter, except that they do not have an argument named METHOD. The HTTP method is instead given by the second word in the function name.

As described in the documentation for ghub-request, it depends on the used method whether the value of the PARAMS argument is used as the query or the payload. For the "PUT", "POST", "PATCH" and "DELETE" methods it is used as the payload.

Function: ghub-wait resource &optional duration &key username auth host ¶

Some API requests result in an immediate successful response even when the requested action has not actually been carried out yet. An example is the request for the creation of a new repository, which doesn’t cause the repository to immediately become available. The Github API documentation usually mentions this when describing an affected resource.

If you want to do something with some resource right after making a request for its creation, then you might have to wait for it to actually be created. This function can be used to do so. It repeatedly tries to access the resource until it becomes available or until a timeout is reached. In the latter case it signals ghub-error.

RESOURCE specifies the resource that this function waits for.

DURATION specifies the maximum number of seconds to wait for, defaulting to 64 seconds. Emacs will block during that time, but the user can abort using C-g.

The first attempt is made immediately and will often succeed. If not, then another attempt is made after two seconds, and each subsequent attempt is made after waiting as long as we already waited between all preceding attempts combined.

See ghub-request’s documentation above for information about the other arguments.

3.5 Non-Github Convenience Wrappers

ghub-request and ghub-METHOD can be used to make a request for any of the supported forge types, but except when making a request for a github instance, then that requires the use of the FORGE argument.

To avoid that, functions named FORGE-request and FORGE-METHOD are also available. The following forms are equivalent, for example:

(ghub-get ... :auth 'PACKAGE :forge 'gitlab)
(glab-get ... :auth 'PACKAGE)

These forms would remain equivalent even if you did not specify a value for the AUTH arguments — but you should not do that if you plan to share your code with others (see Using Ghub in Your Own Package). If you do omit AUTH, then the request is made on behalf of the ghub package, regardless of the symbol prefix of the function you use to do so.

All FORGE-request and FORGE-METHOD functions, including but not limited to ghub-METHOD, are very simple wrappers around ghub-request. They take fewer arguments than ghub-request and instead pass constant values for the arguments METHOD and/or FORGE.

Function: buck-request resource &optional params &key query payload headers unpaginate noerror reader username auth host callback errorback ¶

Function: glab-request resource &optional params &key query payload headers unpaginate noerror reader username auth host callback errorback ¶

Function: gogs-request resource &optional params &key query payload headers unpaginate noerror reader username auth host callback errorback ¶

Wrappers around ghub-request which hardcode the FORGE to either bitbucket, gitlab, gogs or gitea.

Function: buck-get resource &optional params &key query payload headers unpaginate noerror reader username auth host callback errorback ¶

Function: buck-put resource &optional params &key query payload headers unpaginate noerror reader username auth host callback errorback ¶

Function: buck-post resource &optional params &key query payload headers unpaginate noerror reader username auth host callback errorback ¶

Function: buck-delete resource &optional params &key query payload headers unpaginate noerror reader username auth host callback errorback ¶

Function: glab-head resource &optional params &key query payload headers unpaginate noerror reader username auth host callback errorback ¶

Function: glab-get resource &optional params &key query payload headers unpaginate noerror reader username auth host callback errorback ¶

Function: glab-put resource &optional params &key query payload headers unpaginate noerror reader username auth host callback errorback ¶

Function: glab-post resource &optional params &key query payload headers unpaginate noerror reader username auth host callback errorback ¶

Function: glab-patch resource &optional params &key query payload headers unpaginate noerror reader username auth host callback errorback ¶

Function: glab-delete resource &optional params &key query payload headers unpaginate noerror reader username auth host callback errorback ¶

Function: gogs-get resource &optional params &key query payload headers unpaginate noerror reader username auth host callback errorback ¶

Function: gogs-put resource &optional params &key query payload headers unpaginate noerror reader username auth host callback errorback ¶

Function: gogs-post resource &optional params &key query payload headers unpaginate noerror reader username auth host callback errorback ¶

Function: gogs-patch resource &optional params &key query payload headers unpaginate noerror reader username auth host callback errorback ¶

Function: gogs-delete resource &optional params &key query payload headers unpaginate noerror reader username auth host callback errorback ¶

Function: gtea-get resource &optional params &key query payload headers unpaginate noerror reader username auth host callback errorback ¶

Function: gtea-put resource &optional params &key query payload headers unpaginate noerror reader username auth host callback errorback ¶

Function: gtea-post resource &optional params &key query payload headers unpaginate noerror reader username auth host callback errorback ¶

Function: gtea-patch resource &optional params &key query payload headers unpaginate noerror reader username auth host callback errorback ¶

Function: gtea-delete resource &optional params &key query payload headers unpaginate noerror reader username auth host callback errorback ¶

Wrappers around FORGE-METHOD which hardcode the FORGE to either bitbucket, gitlab, gogs or gitea, and the METHOD to the implied method.

Note that buck-head, buck-patch, gogs-head and gtea-head do not exist because the respective APIs do not appear to support these methods.

4.1 Using Ghub in Personal Scripts

You can of course use ghub-request and its wrapper functions in your personal scripts. Unlike when you use Ghub in a package that you distribute for others to use, you don’t have to explicitly specify a package in personal scripts.

;; This is perfectly acceptable in personal scripts ...
(ghub-get "/user")

;; ... and actually equals to
(ghub-get "/user" nil :auth 'ghub)

;; In packages you have to specify the package using AUTH.
(ghub-get "/user" nil :auth 'some-package)

When the AUTH argument is not specified, then a request is made on behalf of the ghub package itself. Like for any other package you have to create a dedicated token of course.

4.2 Using Ghub in Your Own Package

Every package should use its own token. This allows you as the author of some package to only request access to API scopes that are actually needed, which in turn might make it easier for users to trust your package not to do unwanted things.

You have to tell ghub-request on behalf of which package a request is being made by passing the symbol PACKAGE as the value of its AUTH argument.

(ghub-request "GET" "/user" nil :auth 'PACKAGE)

Keep in mind that the users of your package will have to manually create a suitable token. To make that easier, you should not only link to this manual but also prominently mention the scopes the token needs; and explain what they are needed for.

4.3 Forge Limitations and Notes

• There are no default Gitea and Gogs instances so the variables gitea.host and gogs.host are not taken into account.
• Gitea and Gogs do not support limiting a token to certain scopes.
• The Bitbucket API is fairly broken and my willingness to deal with that is extremely limited unless someone pays me vast amounts of money.
• The Gitlab API documentation is not always accurate, though I don’t have an example at hand. It also isn’t structured well, making it occasionally difficult to find the information one is looking for.
• Where one would use user/repo when accessing another forge, one has to use user%2Frepo when accessing Gitlab, e.g.:

  (glab-get "/projects/python-mode-devs%2Fpython-mode")