Gerrit Code Review - JavaScript API
===================================

Gerrit Code Review supports an API for JavaScript plugins to interact
with the web UI and the server process.

Entry Point
-----------

JavaScript is loaded using a standard `<script src='...'>` HTML tag.
Plugins should protect the global namespace by defining their code
within an anonymous function passed to `Gerrit.install()`. The plugin
will be passed an object describing its registration with Gerrit:

[source,javascript]
----
Gerrit.install(function (self) {
  // ... plugin JavaScript code here ...
});
----


[[self]]
Plugin Instance
---------------

The plugin instance is passed to the plugin's initialization function
and provides a number of utility services to plugin authors.

[[self_delete]]
self.delete()
~~~~~~~~~~~~~
Issues a DELETE REST API request to the Gerrit server.

.Signature
[source,javascript]
----
Gerrit.delete(url, callback)
----

* url: URL relative to the plugin's URL space. The JavaScript
  library prefixes the supplied URL with `/plugins/{getPluginName}/`.

* callback: JavaScript function to be invoked with the parsed
  JSON result of the API call. DELETE methods often return
  `204 No Content`, which is passed as null.

[[self_get]]
self.get()
~~~~~~~~~~
Issues a GET REST API request to the Gerrit server.

.Signature
[source,javascript]
----
self.get(url, callback)
----

* url: URL relative to the plugin's URL space. The JavaScript
  library prefixes the supplied URL with `/plugins/{getPluginName}/`.

* callback: JavaScript function to be invoked with the parsed JSON
  result of the API call. If the API returns a string the result is
  a string, otherwise the result is a JavaScript object or array,
  as described in the relevant REST API documentation.

[[self_getPluginName]]
self.getPluginName()
~~~~~~~~~~~~~~~~~~~~
Returns the name this plugin was installed as by the server
administrator. The plugin name is required to access REST API
views installed by the plugin, or to access resources.

[[self_post]]
self.post()
~~~~~~~~~~~
Issues a POST REST API request to the Gerrit server.

.Signature
[source,javascript]
----
self.post(url, input, callback)
----

* url: URL relative to the plugin's URL space. The JavaScript
  library prefixes the supplied URL with `/plugins/{getPluginName}/`.

* input: JavaScript object to serialize as the request payload.

* callback: JavaScript function to be invoked with the parsed JSON
  result of the API call. If the API returns a string the result is
  a string, otherwise the result is a JavaScript object or array,
  as described in the relevant REST API documentation.

[source,javascript]
----
self.post(
  '/my-servlet',
  {start_build: true, platform_type: 'Linux'},
  function (r) {});
----

[[self_put]]
self.put()
~~~~~~~~~~
Issues a PUT REST API request to the Gerrit server.

.Signature
[source,javascript]
----
self.put(url, input, callback)
----

* url: URL relative to the plugin's URL space. The JavaScript
  library prefixes the supplied URL with `/plugins/{getPluginName}/`.

* input: JavaScript object to serialize as the request payload.

* callback: JavaScript function to be invoked with the parsed JSON
  result of the API call. If the API returns a string the result is
  a string, otherwise the result is a JavaScript object or array,
  as described in the relevant REST API documentation.

[source,javascript]
----
self.put(
  '/builds',
  {start_build: true, platform_type: 'Linux'},
  function (r) {});
----

[[self_onAction]]
self.onAction()
~~~~~~~~~~~~~~~
Register a JavaScript callback to be invoked when the user clicks
on a button associated with a server side `UiAction`.

.Signature
[source,javascript]
----
Gerrit.onAction(type, view_name, callback);
----

* type: `'change'`, `'revision'` or `'project'`, indicating which type
  of resource the `UiAction` was bound to in the server.

* view_name: string appearing in URLs to name the view. This is the
  second argument of the `get()`, `post()`, `put()`, and `delete()`
  binding methods in a `RestApiModule`.

* callback: JavaScript function to invoke when the user clicks. The
  function will be passed a link:#ActionContext[action context].

[[self_url]]
self.url()
~~~~~~~~~~
Returns a URL within the plugin's URL space. If invoked with no
parameter the URL of the plugin is returned. If passed a string
the argument is appended to the plugin URL.

[source,javascript]
----
self.url();                    // "https://gerrit-review.googlesource.com/plugins/demo/"
self.url('/static/icon.png');  // "https://gerrit-review.googlesource.com/plugins/demo/static/icon.png"
----


[[ActionContext]]
Action Context
--------------
A new action context is passed to the `onAction` callback function
each time the associated action button is clicked by the user. A
context is initialized with sufficient state to issue the associated
REST API RPC.

[[context_action]]
context.action
~~~~~~~~~~~~~~
An link:rest-api-changes.html#action-info[ActionInfo] object instance
supplied by the server describing the UI button the user used to
invoke the action.

[[context_call]]
context.call()
~~~~~~~~~~~~~~
Issues the REST API call associated with the action. The HTTP method
used comes from `context.action.method`, hiding the JavaScript from
needing to care.

.Signature
[source,javascript]
----
context.call(input, callback)
----

* input: JavaScript object to serialize as the request payload. This
  parameter is ignored for GET and DELETE methods.

* callback: JavaScript function to be invoked with the parsed JSON
  result of the API call. If the API returns a string the result is
  a string, otherwise the result is a JavaScript object or array,
  as described in the relevant REST API documentation.

[source,javascript]
----
context.call(
  {message: "..."},
  function (result) {
    // ... use result here ...
  });
----

[[context_change]]
context.change
~~~~~~~~~~~~~~
When the action is invoked on a change a
link:rest-api-changes.html#change-info[ChangeInfo] object instance
describing the change. Available fields of the ChangeInfo may vary
based on the options used by the UI when it loaded the change.

[[context_delete]]
context.delete()
~~~~~~~~~~~~~~~~
Issues a DELETE REST API call to the URL associated with the action.

.Signature
[source,javascript]
----
context.delete(callback)
----

* callback: JavaScript function to be invoked with the parsed
  JSON result of the API call. DELETE methods often return
  `204 No Content`, which is passed as null.

[source,javascript]
----
context.delete(function () {});
----

[[context_get]]
context.get()
~~~~~~~~~~~~~
Issues a GET REST API call to the URL associated with the action.

.Signature
[source,javascript]
----
context.get(callback)
----

* callback: JavaScript function to be invoked with the parsed JSON
  result of the API call. If the API returns a string the result is
  a string, otherwise the result is a JavaScript object or array,
  as described in the relevant REST API documentation.

[source,javascript]
----
context.get(function (result) {
  // ... use result here ...
});
----

[[context_go]]
context.go()
~~~~~~~~~~~~
Go to a page. Shorthand for link:#Gerrit_go[`Gerrit.go()`].

[[context_hide]]
context.hide()
~~~~~~~~~~~~~~
Hide the currently visible popup displayed by
link:#context_popup[`context.popup()`].

[[context_post]]
context.post()
~~~~~~~~~~~~~~
Issues a POST REST API call to the URL associated with the action.

.Signature
[source,javascript]
----
context.post(input, callback)
----

* input: JavaScript object to serialize as the request payload.

* callback: JavaScript function to be invoked with the parsed JSON
  result of the API call. If the API returns a string the result is
  a string, otherwise the result is a JavaScript object or array,
  as described in the relevant REST API documentation.

[source,javascript]
----
context.post(
  {message: "..."},
  function (result) {
    // ... use result here ...
  });
----

[[context_popup]]
context.popup()
~~~~~~~~~~~~~~~

Displays a small popup near the activation button to gather
additional input from the user before executing the REST API RPC.

The caller is always responsible for closing the popup with
link#context_hide[`context.hide()`]. Gerrit will handle closing a
popup if the user presses `Escape` while keyboard focus is within
the popup.

.Signature
[source,javascript]
----
context.popup(element)
----

* element: an HTML DOM element to display as the body of the
  popup. This is typically a `div` element but can be any valid HTML
  element. CSS can be used to style the element beyond the defaults.

A common usage is to gather more input:

[source,javascript]
----
self.onAction('revision', 'start-build', function (c) {
  var l = c.checkbox();
  var m = c.checkbox();
  c.popup(c.div(
    c.div(c.label(l, 'Linux')),
    c.div(c.label(m, 'Mac OS X')),
    c.button('Build', {onclick: function() {
      c.call(
        {
          commit: c.revision.name,
          linux: l.checked,
          mac: m.checked,
        },
        function() { c.hide() });
    });
});
----

[[context_put]]
context.put()
~~~~~~~~~~~~~
Issues a PUT REST API call to the URL associated with the action.

.Signature
[source,javascript]
----
context.put(input, callback)
----

* input: JavaScript object to serialize as the request payload.

* callback: JavaScript function to be invoked with the parsed JSON
  result of the API call. If the API returns a string the result is
  a string, otherwise the result is a JavaScript object or array,
  as described in the relevant REST API documentation.

[source,javascript]
----
context.put(
  {message: "..."},
  function (result) {
    // ... use result here ...
  });
----

[[context_refresh]]
context.refresh()
~~~~~~~~~~~~~~~~~
Refresh the current display. Shorthand for
link:#Gerrit_refresh[`Gerrit.refresh()`].

[[context_revision]]
context.revision
~~~~~~~~~~~~~~~~
When the action is invoked on a specific revision of a change,
a link:rest-api-changes.html#revision-info[RevisionInfo]
object instance describing the revision. Available fields of the
RevisionInfo may vary based on the options used by the UI when it
loaded the change.

[[context_project]]
context.project
~~~~~~~~~~~~~~~
When the action is invoked on a specific project,
the name of the project.

Action Context HTML Helpers
---------------------------
The link:#ActionContext[action context] includes some HTML helper
functions to make working with DOM based widgets less painful.

* `br()`: new `<br>` element.

* `button(label, options)`: new `<button>` with the string `label`
  wrapped inside of a `div`. The optional `options` object may
  define `onclick` as a function to be invoked upon clicking. This
  calling pattern avoids circular references between the element
  and the onclick handler.

* `checkbox()`: new `<input type='checkbox'>` element.
* `div(...)`: a new `<div>` wrapping the (optional) arguments.
* `hr()`: new `<hr>` element.

* `label(c, label)`: a new `<label>` element wrapping element `c`
  and the string `label`. Used to wrap a checkbox with its label,
  `label(checkbox(), 'Click Me')`.

* `prependLabel(label, c)`: a new `<label>` element wrapping element `c`
  and the string `label`. Used to wrap an input field with its label,
  `prependLabel('Greeting message', textfield())`.

* `textarea(options)`: new `<textarea>` element. The options
  object may optionally include `rows` and `cols`. The textarea
  comes with an onkeypress handler installed to play nicely with
  Gerrit's keyboard binding system.

* `textfield()`: new `<input type='text'>` element.  The text field
  comes with an onkeypress handler installed to play nicely with
  Gerrit's keyboard binding system.

* `span(...)`: a new `<span>` wrapping the (optional) arguments.

* `msg(label)`: a new label.

[[Gerrit]]
Gerrit
------

The `Gerrit` object is the only symbol provided into the global
namespace by Gerrit Code Review. All top-level functions can be
accessed through this name.

[[Gerrit_delete]]
Gerrit.delete()
~~~~~~~~~~~~~~~
Issues a DELETE REST API request to the Gerrit server. For plugin
private REST API URLs see link:#self_delete[self.delete()].

.Signature
[source,javascript]
----
Gerrit.delete(url, callback)
----

* url: URL relative to the Gerrit server. For example to access the
  link:rest-api-changes.html[changes REST API] use `'/changes/'`.

* callback: JavaScript function to be invoked with the parsed
  JSON result of the API call. DELETE methods often return
  `204 No Content`, which is passed as null.

[source,javascript]
----
Gerrit.delete(
  '/changes/myProject~master~I8473b95934b5732ac55d26311a706c9c2bde9940/topic',
  function () {});
----

[[Gerrit_get]]
Gerrit.get()
~~~~~~~~~~~~
Issues a GET REST API request to the Gerrit server. For plugin
private REST API URLs see link:#self_get[self.get()].

.Signature
[source,javascript]
----
Gerrit.get(url, callback)
----

* url: URL relative to the Gerrit server. For example to access the
  link:rest-api-changes.html[changes REST API] use `'/changes/'`.

* callback: JavaScript function to be invoked with the parsed JSON
  result of the API call. If the API returns a string the result is
  a string, otherwise the result is a JavaScript object or array,
  as described in the relevant REST API documentation.

[source,javascript]
----
Gerrit.get('/changes/?q=status:open', function (open) {
  for (var i = 0; i < open.length; i++) {
    console.log(open.get(i).change_id);
  }
});
----

[[Gerrit_getPluginName]]
Gerrit.getPluginName()
~~~~~~~~~~~~~~~~~~~~~~
Returns the name this plugin was installed as by the server
administrator. The plugin name is required to access REST API
views installed by the plugin, or to access resources.

Unlike link:#self_getPluginName[`self.getPluginName()`] this method
must guess the name from the JavaScript call stack. Plugins are
encouraged to use `self.getPluginName()` whenever possible.

[[Gerrit_go]]
Gerrit.go()
~~~~~~~~~~~
Updates the web UI to display the view identified by the supplied
URL token. The URL token is the text after `#` in the browser URL.

[source,javascript]
----
Gerrit.go('/admin/projects/');
----

If the URL passed matches `http://...`, `https://...`, or `//...`
the current browser window will navigate to the non-Gerrit URL.
The user can return to Gerrit with the back button.

[[Gerrit_install]]
Gerrit.install()
~~~~~~~~~~~~~~~~
Registers a new plugin by invoking the supplied initialization
function. The function is passed the link:#self[plugin instance].

[source,javascript]
----
Gerrit.install(function (self) {
  // ... plugin JavaScript code here ...
});
----

[[Gerrit_post]]
Gerrit.post()
~~~~~~~~~~~~~
Issues a POST REST API request to the Gerrit server. For plugin
private REST API URLs see link:#self_post[self.post()].

.Signature
[source,javascript]
----
Gerrit.post(url, input, callback)
----

* url: URL relative to the Gerrit server. For example to access the
  link:rest-api-changes.html[changes REST API] use `'/changes/'`.

* input: JavaScript object to serialize as the request payload.

* callback: JavaScript function to be invoked with the parsed JSON
  result of the API call. If the API returns a string the result is
  a string, otherwise the result is a JavaScript object or array,
  as described in the relevant REST API documentation.

[source,javascript]
----
Gerrit.post(
  '/changes/myProject~master~I8473b95934b5732ac55d26311a706c9c2bde9940/topic',
  {topic: 'tests', message: 'Classify work as for testing.'},
  function (r) {});
----

[[Gerrit_put]]
Gerrit.put()
~~~~~~~~~~~~
Issues a PUT REST API request to the Gerrit server. For plugin
private REST API URLs see link:#self_put[self.put()].

.Signature
[source,javascript]
----
Gerrit.put(url, input, callback)
----

* url: URL relative to the Gerrit server. For example to access the
  link:rest-api-changes.html[changes REST API] use `'/changes/'`.

* input: JavaScript object to serialize as the request payload.

* callback: JavaScript function to be invoked with the parsed JSON
  result of the API call. If the API returns a string the result is
  a string, otherwise the result is a JavaScript object or array,
  as described in the relevant REST API documentation.

[source,javascript]
----
Gerrit.put(
  '/changes/myProject~master~I8473b95934b5732ac55d26311a706c9c2bde9940/topic',
  {topic: 'tests', message: 'Classify work as for testing.'},
  function (r) {});
----

[[Gerrit_onAction]]
Gerrit.onAction()
~~~~~~~~~~~~~~~~~
Register a JavaScript callback to be invoked when the user clicks
on a button associated with a server side `UiAction`.

.Signature
[source,javascript]
----
Gerrit.onAction(type, view_name, callback);
----

* type: `'change'` or `'revision'`, indicating what sort of resource
  the `UiAction` was bound to in the server.

* view_name: string appearing in URLs to name the view. This is the
  second argument of the `get()`, `post()`, `put()`, and `delete()`
  binding methods in a `RestApiModule`.

* callback: JavaScript function to invoke when the user clicks. The
  function will be passed a link:#ActionContext[ActionContext].

[[Gerrit_refresh]]
Gerrit.refresh()
~~~~~~~~~~~~~~~~
Redisplays the current web UI view, refreshing all information.

[[Gerrit_url]]
Gerrit.url()
~~~~~~~~~~~~
Returns the URL of the Gerrit Code Review server. If invoked with
no parameter the URL of the site is returned. If passed a string
the argument is appended to the site URL.

[source,javascript]
----
Gerrit.url();        // "https://gerrit-review.googlesource.com/"
Gerrit.url('/123');  // "https://gerrit-review.googlesource.com/123"
----

For a plugin specific version see link:#self_url()[`self.url()`].

GERRIT
------
Part of link:index.html[Gerrit Code Review]