How can I access an API which requires OAuth 2.0 authorization, such as Google APIs

Some REST APIs, such as Google Analytics' Core Reporting API, require authorization tokens, which must be obtained before the required data can be downloaded. Can anyone share or point to code on how to do this in MATLAB?

In particular I'm looking to use an App in the MATLAB-based ThingSpeak service to automatically download the number of unique visitors to my website from Google Analytics (behind an authentication firewall) daily, and save that information to a ThingSpeak channel.

[Yuebin Zhou]

Can you further explain what you want to do with MATLAB?

Answer 1

[YH]

Go to the below link in any browser to retrieve your authorization code, using your client id:

https://accounts.google.com/o/oauth2/auth?client_id=YOUR_CLIENT_ID_FROM_GOOGLE_DEVELOPER_CONSOLE&redirect_uri=urn:ietf:wg:oauth:2.0:oob&scope=https://www.googleapis.com/auth/analytics.readonly&response_type=code

Then, try the below, substituting your client id, client secret, and authorization code from before.

client_id = 'YOUR CLIENT ID FROM GOOGLE DEVELOPER CONSOLE';
client_secret = 'YOUR CLIENT SECRET FROM GOOGLE DEVELOPER CONSOLE';

url = 'https://accounts.google.com/o/oauth2/token';
redirect_uri = 'urn:ietf:wg:oauth:2.0:oob';
code = 'YOUR AUTHORIZATION CODE';

data = [...
 'redirect_uri=', redirect_uri,... 
 '&client_id=', client_id,...
 '&client_secret=', client_secret,...
 '&grant_type=', 'authorization_code',...
 '&code=', code];

response = webwrite(url,data);
access_token = response.access_token;

% save access token for future calls
headerFields = {'Authorization', ['Bearer ', access_token]};
options = weboptions('HeaderFields', headerFields, 'ContentType','json');

References:

Linda Lawton | Google Authentication with CURL

MathWorks | Write Form-Encoded Character Array

Stack Overflow | Integrating MATLAB with Google BigQuery via REST API

[Scott Snowden]

Thank you! This solved my problem, although I can't find a solution for 'send()'. Just to note - at the end of this, you'll need to call

webread('https://yoururlhere.com',options)

[kees]

Dear YH,

I try to do the same thing for the freesound website, which expects this format:

"Authorization: Bearer {{access_token}}" 'httpss://freesound.org/apiv2/sounds/14854/download/'

(from https://freesound.org/docs/api/authentication.html#authentication )

I have tried to rebuild your example, but haven't succeeded, could you please point me in the right direction?

many thanks!

Kees

Answer 2

[Hans Scharler]

To download data from ThingSpeak, you only need to send a request to a channel (public channel) or to channel with a read API key (private channel).

Here's how to read the last data from my private ThingSpeak channel that contains the last 10 power measurements for my house.

[data, time] = thingSpeakRead(readChannelID, 'Field', fieldID1, 'NumPoints', 10, 'ReadKey', readAPIKey);

To get access to thingSpeakRead, you need to install the ThingSpeak Support Toolbox.

You can also use "webread".

[data] = webread('https://api.thingspeak.com/channels/97871/fields/1.json?results=10&api_key=7MOXB8G515OAD94Q');
data.feeds.field1

[Oliver Woodford]

Thanks, Hans. However, I'm not looking to download data from a ThingSpeak channel. I want to download data from Google Analytics, data which is hidden behind an authentication process. I've edited my question to make that clearer.