Google Drive SDK jsonRequest header meaning - json

Question

The google drive sdk documentation in "Work with Files and Folders" section says something about the header of a post. Which is:
POST https://www.googleapis.com/drive/v2/files
Authorization: Bearer {ACCESS_TOKEN}
Content-Type: application/json
What does this mean? Does the header really exist on a jsonRequest? Where should this post go to? Should we type the header first, then, put in the json request along with the json string then post it to the server? Or does the ACCESS_TOKEN and the rest of the information be posted along with the URL as a get, like this?
POST https://www.googleapis.com/drive/v2/files?access_token={ACCESS_TOKEN}&etc=whatever&...
I understand that you need to be given an access token or an API key, but where does this go? Does this go on the url string, or does it go inside a post value or jsonRequest?
I've read the jsonRequest in json.org, but still can not get it. Do I need to consider what my content-type, content-length, and content-encoding really means? And if ever I will, where should all of these information go?
Sometimes, the answer is just staring right at my face, and before I know it, I already miss the point. So, can anybody shed me some light?

Answer 1

The Google Drive API is a RESTFul API using HTTP requests as the communication mechanism. The Authorization header is an HTTP header that needs to be sent along the request to authorize it. JSON is only used as the resource representation.
However, the Drive API also supports passing the OAuth 2.0 access token as a ?access_token= query parameter which can be more convenient for you.
If you are using one of supported client libraries, all this is taken care of for you through class abstractions.

Answer 2

The header is a standard part of an HTTP request. The standards of an http request are header fields and request methods.
POST https://www.googleapis.com/drive/v2/files
Request methods on this example is a POST and it sends the data to google drive api server. This means, the Google Drive API will accept POST requests.
Authorization: Bearer {ACCESS_TOKEN}
The Authorization, in this case, is an ACCESS_TOKEN which is the API_KEY. The server may receive also a GET request. The server checks to see if the user is authorized before it does its process: create, delete, update, or get files (depending on what the Http Request json data sends).
Content-Type: application/json
The Content-Type tells the server that the Mime Type of the HTTP request that will be sent is a json string. The Mime Type may be already a standard for the server, which means that you don’t even have to put it anywhere in your code because it assumes that you will be sending a json string, and it will receive it once you do POST. Otherwise, it will give an error. Content-Type field will always receive the Mime Type. (For a list of Mime Types, you may refer to http://en.wikipedia.org/wiki/MIME_type.)
Since HTTP Header is a standard, you will need to know what type of standards there are that Google Drive API server uses. Then, follow wherever the header fields are placed. For example, the ACCESS_TOKEN is located in the url string as a GET, and json string is located in a POST. (For a list of HTTP Header, you can also get a reference from http://en.wikipedia.org/wiki/List_of_HTTP_header_fields.)