Inline Documentation for RESTful web APIs Introduction with a small example. http://apidocjs.com

1. APIDOCInline Documentation for RESTful web APIs
Introduction with a small example.
http://apidocjs.com

2. What does apiDoc ?
apiDoc
… creates a Documentation HTML-Page
… use API-Descriptions from your source code
For who ?
apiDoc can be used with any programming language, that allow
block documentation:
/**
* This is a comment.
*/

3. Where i find apiDoc ?
apiDoc is Open Source and distributed over NPM and github
Visit: http://apidocjs.com
Special functions
apiDoc
… support own created Templates
… includes History
… compare old and new API-Method Versions
… allows frontend Developer to see what changed
… support Inherit
… reuse of Documentation parts
… extendable
… you can create your own Documentation Methods

4. Ok, let us begin...
apiDoc is a node module, so install Node.js first:
http://nodejs.org
Node.js includes „npm“, a package manager for node.
Install apiDoc
[sudo] npm install -g apidoc
We install apiDoc global, so you can access it from everywhere.

5. EXAMPLE PROJECT
We use a simple static JavaScript example.
We ignore routing, validation or database operations.
This are only small parts of apiDocs functions, for all visit http://apidocjs.com
There is also a complex example: http://apidocjs.com/#example-full

6. Create a new directory „my_project“.
Within that dir create a file „example.js“.
example.js
var currentUser = {
name: 'Mary'
};
function getUser() {
return { code: 200, data: currentUser };
}
function setName(name) {
if(name.length === 0) {
return { code: 404, message: 'NameEmptyError' };
}
currentUser.name = name;
return { code: 204 };
}

7. A basic doc
Above „function getUser“ we place a basic documentation block
/**
* @api {get} /user Request User information
* @apiName GetUser
* @apiGroup User
*/
function getUser() {
return { code: 200, data: currentUser };
}
This 3 parameters are required!
@api describes the path of the Method that clients call.
@apiName is a unique Name, you can name as you want, for simplicity i prefer
„Type of Method“ + „Name of Method“ e.g. {get} and „/user“ => GetUser.
@apiGroup is the name of the group to which this method belongs. The group will be
used for Navigation.

8. By default apiDoc search for all „.jjs“ files in current directory and sub directories.
You can change the includeFilter, call „apidoc -h“ for details.
apiDoc created a new HTML-Page in directory „doc“.
From command line run within „my_project“ directory:
apidoc

9. Open „doc/index.html“ in your Browser
We see the rudimentary Webpage, with Navigation left and Content right.
We have a group „User“ and within that group an API-Method „GET /user“

10. Describe the API-Answer
Now we add success return parameters
/**
* @api {get} /user Request User information
* @apiName GetUser
* @apiGroup User
*
* @apiSuccess {String} name The users name.
*/
function getUser() {
return { code: 200, data: currentUser };
}
apidoc
Run apiDoc again, it will overwrite the „doc“ Directory

11. Now we have a little more Information and see what „GET /user“ returns on a
successful reply „Success 200“.

12. Add a Version and example Code
We add a Version (Format “major.minor.patch”, see http://semver.org for details)
and we add an example code, that shows what will be return in case of success
/**
* @api {get} /user Request User information
* @apiName GetUser
* @apiGroup User
* @apiVersion 0.1.0
*
* @apiSuccess {String} name The users name.
*
* @apiSuccessExample Example data on success:
* {
* name: 'Paul'
* }
*/
function getUser() {
return { code: 200, data: currentUser };
}

13. In the right dropdown box we see now the Version „0.1.0“ and under „Success 200“
our integrated example.

14. VERSIONING
If you work in a Team and some Programmer work an the API backend and some on
Frontend Client, it is important to know what changed in a new Release.
Especially during developing an Application, many things can change.

15. An API Method change
Create a new file „_apidoc.js“.
Put only the documentation Block from „getUser“ in that file:
_apidoc.js
/**
* @api {get} /user Request User information
* @apiName GetUser
* @apiGroup User
* @apiVersion 0.1.0
*
* @apiSuccess {String} name The users name.
*
* @apiSuccessExample Example data on success:
* {
* name: 'Paul'
* }
*/
„_apidoc.js“ will be our history file and contains old documentation blocks.

16. Now we change the documentation block in „example.js“
example.js
/**
* @api {get} /user Request User information
* @apiName GetUser
* @apiGroup User
* @apiVersion 0.2.0
*
* @apiSuccess {String} name The users name.
* @apiSuccess {Number} age Calculated age from Birthday
*
* @apiSuccessExample Example data on success:
* {
* name: 'Paul',
* age: 27
* }
*/
function getUser() {
return { code: 200, data: currentUser };
}

17. After call „apidoc“ and open „doc/index.html“ you see now Version „0.2.0“ with the
Field „age“ and the changed example.

18. And now the magic...

19. Select from Dropdown „0.2.0“ the Version „0.1.0“.
You see now a comparison from the 2 Versions. Green marked content indicates the
Fields that are added to Version „0.2.0“.

20. In the future, when you made more changes to an API-Method, simply copy and add
the complete documentation block to the history file „_apidoc.js“.
Leave the old blocks as they are.
Then you have a Documentation where everybody can see any change of your API.

21. PARAMS AND ERRORS
We take now a quick look at how to add Parameters, that an API-Method need and
how we return errors.

22. We add now a documentation to our second function „setName“.
example.js
/**
* @api {put} /user Change User
* @apiName PutUser
* @apiGroup User
* @apiVersion 0.1.0
*
* @apiParam {String} name New name of the user
*
* @apiError NameEmptyError The name was empty. Minimum of <code>1</code> character is required.
*/
function setName(name) {
if(name.length === 0) {
return { code: 404, message: 'NameEmptyError' };
}
currentUser.name = name;
return { code: 204 };
}

23. You will see now the new „Change User“ entry in navigation and the content for the
API-Method.

24. Thank you and have a productive use !
For more Information visit http://apidocjs.com
Author: Peter Rottmann
peter@apidocjs.com