Talking to Twitter’s REST API v1.1 with R

The up-to-date tutorial on using Twitter API on Linux and Windows from R may be found here.

twitterIn this text I am going to describe a very straightforward way of how to make use of Twitter’s REST API v1.1. I put some code together for that purpose, so that requesting data just needs the API URL, the API parameters and a vector containing the OAuth parameters.

Before you can get started you have to login to your Twitter account on dev.twitter.comcreate an application and generate an “Access Token” for it. So let’s jump right in and fetch IDs of 10 followers of @hrw (Human Rights Watch). The necessary code is located on GitHub – download all three files and then you can just edit the example below as suggested.

The result is a JSON containing the IDs of 10 followers (and in case you wonder why it looks so pretty – it’s thanks to jsonlite::prettify()):

OAuth Version 1

Twitter provides access to its service via a REST API whose current version is 1.1. Authorization is realized through OAuth version 1.0a. Due to that, handling the API is less trivial than just appending your password to the request – but also considerably more secure. Opposed to standard password-based authentication – OAuth distinguishes between the server (Twitter), the third-party client (the program calling the API) and the resource owner (the owner of the API account) by specifying an authentication flow where the resource owner grants access to the third-party client by programmatically providing a secret token in the end. But as in this case the third-party client and the resource owner are effectively identical the process simplifies to just manually creating an access token and its corresponding “token secret” and then using those directly within the script. Referring to the OAuth 1 authentication flow chart – we can skip steps A to F and focus entirely on G.

Signing the Request for OAuth1

The authorization of a request itself happens by glueing together a string which contains all the details about that request – URL, query parameters, OAuth keys and values – and then signing this so called “signature base string” with the two secret tokens – oauth_token_secret and consumer_secret applying an algorithm referred to as HMAC-SHA1. HMAC-SHA1 is provided by the digest package. What you get in the end after some more processing is the oauth_signature which is sent along with the request and verified by the server. The creation of that signature is implemented in RTwitterAPI/oauth1_signature.R – a detailed description may be found here.

Structure of the GET Request

The GET request which is finally sent via RCurl needs a propperly set up header containing an “Authentication” section providing all the various oauth_* settings. This part is implemented in RTwitterAPI/twitter_api_call.R. The meaning of the oauth_*  key/values, as well as the composition of the header is described here.

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6 thoughts on “Talking to Twitter’s REST API v1.1 with R

  1. Hello Raffael,

    I’ve forked your code, and doesn`t work for me yet.

    Just to be sure I have correctly understood, I have filled

    oauth_consumer_key with what in twitter is called API KEY,
    consumer_secret with what in twitter is called API SECRET
    oauth_token_secret with what in twitter is called ACCESS TOKEN SECRET

    All the other field I left as in your github.

    Then I get:
    Error in function (type, msg, asError = TRUE) : SSL certificate problem, verify that the CA cert is OK. Details: error:14090086:SSL routines:SSL3_GE
    T_SERVER_CERTIFICATE:certificate verify failed

    Could be the fact that I am trying this on windows?

    Thank you in advance


    • Hi Massimo!

      I can confirm this error message for Windows 7 – just tried it. Will try again with Ubuntu tomorrow to figure out whether it’s the OS that is causing the issue.

      Thanks for your feedback!


        • Googling for this error message uncovers that this seems to be a quite popular issue. :/ Just tried two suggested solutions from SO – to no avail. My suggestion – if you have a choice – switch to Linux ;) I am not kidding you – Ubuntu is very easy to handle for beginners and a lot of tasks revolving around dealing with data programmatically do get much easier!

          Sorry for the inconvenience, though!

        • Estimado,

          Pudo solucionar el error? me aparece el mismo error ejecutando R.

          Error en function (type, msg, asError = TRUE) :
          SSL certificate problem, verify that the CA cert is OK. Details:
          error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed

          Alguien puede ayudar?

          • Hola Fabián,

            gracias por su pregunta. Lo sentimos, pero no tengo ni idea de cómo resolver este problema. Por favor díganos en caso de que te diste cuenta.

            Saludos compañero


            PD: Esta respuesta es impulsado por Google Translate :)

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