How to exchange a requested TOKEN for an access TOKEN from Twitter in PERL

Finally, we're here at the last part of OAuth process, exchanging the requested token for an access token. I assume you were able to follow my last 2 posts below.

• How to request OAuth TOKEN from Twitter in PERL 
• How to authorize OAuth TOKEN from Twitter in PERL 

To get an access token, we need the OAuth Token, and Verifier from the previous post.

Just follow the simple steps below to gain an access token which we will use to access Twitter API in users behalf. This is likely the same when requesting a token, the only difference are the parameters we pass on.

1. Install all the libraries you need.

• LWP::UserAgent
• HTTP::Cookies
• Digest::MD5
• Digest::SHA
• POSIX

2. Initialize the libraries

require LWP::UserAgent;

use strict;
use warnings;

use HTTP::Cookies;

use Digest::MD5 qw(md5 md5_hex md5_base64);
use Digest::SHA qw(sha1 sha1_hex sha1_base64 hmac_sha1 hmac_sha1_hex hmac_sha1_base64);

use POSIX qw(strftime);

my $lwpua = LWP::UserAgent->new;

3. Setup the UserAgent and HTTP header with the name "Authorization" equal to "OAuth".

my $uagent = "Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.0.6) Gecko/20060728 Firefox/1.5.0.6";
my @header = ('Referer' => 'https://api.twitter.com/',
             'User-Agent' => $uagent,
             'Authorization' => 'OAuth');

4. Build the signature base and signing key. Please take note that some parameters should be URL Encoded, see the post for the PERL function that you can use - URLENCODE sub function in PERL.

You need the consumer key and secret which was generated by Twitter upon registration.

You also need the Oauth Token and Verifier which you get when authorizing the requested token.

To generate NONCE, we use Digest::MD5::md5_base64() passing the localtime(). We do it twice to make it much UNIQUE.

Timestamp was generated by using POSIX::strftime() with date format UNIXTIME as "%s".

# build signature base
my $strToken = "<your oauth token>";
my $strVerifier = "<your oauth verifier>";

my $post_url = "https://api.twitter.com/oauth/access_token";
my $nonce = md5_base64(localtime()).md5_base64(localtime());
my $timestamp = strftime('%s', localtime);
my $method = "HMAC-SHA1";
my $version = "1.0";
my $consumer_key = "<your consumer key generated upon registration>";
my $consumer_secret = "<your consumer secret generated upon registration>";

my $post_urlenc = &urlencode($post_url);

my $oauth_data = "oauth_consumer_key=$consumer_key&oauth_nonce=$nonce&oauth_signature_method=$method&oauth_timestamp=$timestamp&oauth_token=$strToken&oauth_verifier=$strVerifier&oauth_version=$version";
my $oauth_dataenc = &urlencode($oauth_data);

my $sign_base = "POST&".$post_urlenc."&".$oauth_dataenc;
my $sign_key = $consumer_secret."&";

5. Generate the OAuth Signature using HMAC-SHA1 method.

my $oauth_sign = hmac_sha1_base64($sign_base, $sign_key)."=";

6. Post an OAuth request with all the parameters you passed on step #4.

my $response = $lwpua->post($post_url,
                        ['oauth_token' => $strToken,
                         'oauth_verifier' => $strVerifier,
                         'oauth_consumer_key' => $consumer_key,
                         'oauth_nonce' => $nonce,
                         'oauth_signature_method' => $method,
                         'oauth_signature' => $oauth_sign,
                         'oauth_timestamp' => $timestamp,
                         'oauth_version' => $version], @header);
my $form_data = $response->content;

7. Get the return value: oauth_token, oauth_token_secret, user_id, and screen_name

$form_data =~ s/\n//g;
$form_data =~ /^oauth_token=(.*?)&oauth_token_secret=(.*?)&user_id=(.*?)&screen_name=(.*?)\s*$/gi;

my $oauth_token = $1;
my $oauth_secret = $2;
my $user_id = $3;
my $screen_name = $4;


Hope you like it! Please see the complete code below. Thank you for reading.

#!/usr/bin/perl

require LWP::UserAgent;

use strict;
use warnings;

use HTTP::Cookies;

use Digest::MD5 qw(md5 md5_hex md5_base64);
use Digest::SHA qw(sha1 sha1_hex sha1_base64 hmac_sha1 hmac_sha1_hex hmac_sha1_base64);

use POSIX qw(strftime);


my $lwpua = LWP::UserAgent->new;

my $uagent = "Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.0.6) Gecko/20060728 Firefox/1.5.0.6";
my @header = ('Referer' => 'https://api.twitter.com/',
             'User-Agent' => $uagent,
             'Authorization' => 'OAuth');

# build signature base
my $strToken = "<your oauth token>";
my $strVerifier = "<your oauth verifier>";

my $post_url = "https://api.twitter.com/oauth/access_token";
my $nonce = md5_base64(localtime()).md5_base64(localtime());
my $timestamp = strftime('%s', localtime);
my $method = "HMAC-SHA1";
my $version = "1.0";
my $consumer_key = "<your consumer key generated upon registration>";
my $consumer_secret = "<your consumer secret generated upon registration>";

my $post_urlenc = &urlencode($post_url);
my $oauth_data = "oauth_consumer_key=$consumer_key&oauth_nonce=$nonce&oauth_signature_method=$method&oauth_timestamp=$timestamp&oauth_token=$strToken&oauth_verifier=$strVerifier&oauth_version=$version";
my $oauth_dataenc = &urlencode($oauth_data);

my $sign_base = "POST&".$post_urlenc."&".$oauth_dataenc;
my $sign_key = $consumer_secret."&";

  # oauth signature
my $oauth_sign = hmac_sha1_base64($sign_base, $sign_key)."=";

# post oauth request
my $response = $lwpua->post($post_url,
                        ['oauth_token' => $strToken,
                         'oauth_verifier' => $strVerifier,
                         'oauth_consumer_key' => $consumer_key,
                         'oauth_nonce' => $nonce,
                         'oauth_signature_method' => $method,
                         'oauth_signature' => $oauth_sign,
                         'oauth_timestamp' => $timestamp,
                         'oauth_version' => $version], @header);
my $form_data = $response->content;

$form_data =~ s/\n//g;
$form_data =~ /^oauth_token=(.*?)&oauth_token_secret=(.*?)&user_id=(.*?)&screen_name=(.*?)\s*$/gi;

my $oauth_token = $1;
my $oauth_secret = $2;
my $user_id = $3;
my $screen_name = $4;

print "$oauth_token|$oauth_secret|$user_id|$screen_name\n";
print "done!";


sub urlencode
{
  my ($url) = @_;

  $url =~ s/([^A-Za-z0-9_.-])/sprintf("%%%02X", ord($1))/seg;
  return $url;
}



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How to authorize OAuth TOKEN from Twitter in PERL

I assume you read my previous post - How to request OAuth TOKEN from Twitter in PERL before reading this post. You need the OAuth Token and Secret to proceed to this process.

On this post, we will login to twitter via back-end, please see post - Login to Twitter via backend using PERL on how to do it. Once the user had been logged in, we will authorize our application to post tweet and access users information in users behalf.

This post will outputted an OAuth Token and Verifier which you will use to Access Token "final oauth process" to get the OAuth Token and OAuth Secret.

Follow the simple steps below to authorize your application.

1. Install the following libraries.

• LWP::UserAgent
• HTTP::Cookies

2. Initialize the libraries.

require LWP::UserAgent;
use HTTP::Cookies;
my $lwpua = LWP::UserAgent->new;

3. Setup UserAgent, HTTP Header, and Cookies.

my $uagent = "Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.0.6) Gecko/20060728 Firefox/1.5.0.6";
my @header = ('Referer' => 'https://api.twitter.com/',
             'User-Agent' => $uagent);

my $cookie_file = "/home/wapps/tweext/cookies/twitter/cookies.$intMsisdn.dat";
my $cookie_jar = HTTP::Cookies->new(
                file => $cookie_file,
                autosave => 1,
                ignore_discard => 1);

my $lwpua->cookie_jar($cookie_jar);

4. Post the OAuth Token with Username and Password to authorize URL - https://api.twitter.com/oauth/authorize

my $strToken = "<your oauth token>";
my $strUser = "<your twitter username>";
my $strPass = "<your twitter password>";

my $response = $lwpua->post("https://api.twitter.com/oauth/authorize",
                          ['oauth_token' => $strToken,
                           'session[username_or_email]' => $strUser,
                           'session[password]' => $strPass], @header);
my $cookie_jar->extract_cookies( $response );
my $cookie_jar->save;

$form_data = $response->content;

5. Get the OAuth Token and Oauth Verifier from the output returned by step #4.

$form_data =~ s/\n//g;
$form_data =~ /meta http-equiv="refresh" content="0;url=(.*?)\?oauth_token=(.*?)&oauth_verifier=(.*?)"/ig;

my $oauth_token = $2;
my $oauth_verif = $3;

unlink($cookie_file);



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Please see the complete code below. Thank you for reading this post.

#!/usr/bin/perl

require LWP::UserAgent;

use strict;
use warnings;

use HTTP::Cookies;

my $lwpua = LWP::UserAgent->new;

my $uagent = "Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.0.6) Gecko/20060728 Firefox/1.5.0.6";
my @header = ('Referer' => 'https://api.twitter.com/',
             'User-Agent' => $uagent);

my $cookie_file = "/home/wapps/tweext/cookies/twitter/cookies.$intMsisdn.dat";
my $cookie_jar = HTTP::Cookies->new(
                file => $cookie_file,
                autosave => 1,
                ignore_discard => 1);

my $lwpua->cookie_jar($cookie_jar);

my $strToken = "<your oauth token>";
my $strUser = "<your twitter username>";
my $strPass = "<your twitter password>";

my $response = $lwpua->post("https://api.twitter.com/oauth/authorize",
                          ['oauth_token' => $strToken,
                           'session[username_or_email]' => $strUser,
                           'session[password]' => $strPass], @header);
my $cookie_jar->extract_cookies( $response );
my $cookie_jar->save;

$form_data = $response->content;

$form_data =~ s/\n//g;
$form_data =~ /meta http-equiv="refresh" content="0;url=(.*?)\?oauth_token=(.*?)&oauth_verifier=(.*?)"/ig;

my $oauth_token = $2;
my $oauth_verif = $3;

unlink($cookie_file);



1;

How to request OAuth TOKEN from Twitter in PERL

For us to be able to request for a token, the first thing you have to do is to register your application.

To register an app, access the Client Applications page of Twitter. Registering your application allows twitter to identify your application. Remember not to reveal your consumer secrets with anyone.

While creating an application, you will be asked whether your application is a client or browser application, choose browser for this post.



Client applications need not to enter a callback URL. In fact, web applications need not to supply a callback URL either, but as best practice, you should submit your oauth_callback_url on every token request, explicitly declaring what you want the callback to be. This will also be needed to identify the variables we need since we're doing it backend.

You will also be asked for an access type, choose "read and write" for you to be able to post tweet eventually.



After registering your application, you will have the 2 important details below.

• Consumer Key
• Consumer Secret

Once you have those details, we are now ready to do the coding part. Just follow the simple steps below and you will be able to retrieve a token from Twitter.

Please take note that this token is not yet ready to access twitter on users behalf. The returned token by this process will be use to AUTHORIZE "next to this oauth process" and ACCESS TOKEN "final oauth process".

1. Install the libraries you need.

• LWP::UserAgent
• HTTP::Cookies
• Digest::MD5
• Digest::SHA
• POSIX

2. Initialize the following libraries.

require LWP::UserAgent;

use HTTP::Cookies;

use Digest::MD5 qw(md5 md5_hex md5_base64);
use Digest::SHA qw(sha1 sha1_hex sha1_base64 hmac_sha1 hmac_sha1_hex hmac_sha1_base64);

use POSIX qw(strftime);

my $lwpua = LWP::UserAgent->new;

3. Setup the UserAgent and HTTP header with the name "Authorization" equal to "OAuth".

my $uagent = "Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.0.6) Gecko/20060728 Firefox/1.5.0.6";
my @header = ('Referer' => 'https://api.twitter.com/',
             'User-Agent' => $uagent,
             'Authorization' => 'OAuth');

4. Build the signature base and signing key. Please take note that some parameters should be URL Encoded, see the post for the PERL function that you can use - URLENCODE sub function in PERL.

You need the callback URL which you define during client registration, and the consumer key and secret which was generated by Twitter upon registration.

To generate NONCE, we use Digest::MD5::md5_base64() passing the localtime(). We do it twice to make it much UNIQUE.

Timestamp was generated by using POSIX::strftime() with date format UNIXTIME as "%s".

my $post_url = "https://api.twitter.com/oauth/request_token";
my $callback_url = "<your callback url define on client registration>";
my $nonce = md5_base64(localtime()).md5_base64(localtime());
my $timestamp = strftime('%s', localtime);
my $method = "HMAC-SHA1";
my $version = "1.0";
my $consumer_key = "<your consumer key generated upon registration>";
my $consumer_secret = "<your consumer secret generated upon registration>";

my $callback_urlenc = &urlencode($callback_url);
my $post_urlenc = &urlencode($post_url);

my $oauth_data = "oauth_callback=$callback_urlenc&oauth_consumer_key=$consumer_key&oauth_nonce=$nonce&oauth_signature_method=$method&oauth_timestamp=$timestamp&oauth_version=$version";
my $oauth_dataenc = &urlencode($oauth_data);

my $sign_base = "POST&".$post_urlenc."&".$oauth_dataenc;
my $sign_key = $consumer_secret."&";

5. Generate the OAuth Signature using HMAC-SHA1 method.

my $oauth_sign = hmac_sha1_base64($sign_base, $sign_key)."=";

6. Post an OAuth request with all the parameters you passed on step #4.

my $response = $lwpua->post($post_url,
                        ['oauth_callback' => $callback_url,
                         'oauth_consumer_key' => $consumer_key,
                         'oauth_nonce' => $nonce,
                         'oauth_signature_method' => $method,
                         'oauth_signature' => $oauth_sign,
                         'oauth_timestamp' => $timestamp,
                         'oauth_version' => $version], @header);
my $form_data = $response->content;

7. Get the return value: oauth_token, oauth_token_secret, and oauth_callback_confirmed

$form_data =~ s/\n//g;
$form_data =~ /^oauth_token=(.*?)&oauth_token_secret=(.*?)&oauth_callback_confirmed=(.*?)\s*$/gi;

my $oauth_token = $1;
my $oauth_secret = $2;
my $oauth_confirm = $3;


Hope you like it!! Please see the complete code below.

#!/usr/bin/perl

require LWP::UserAgent;

use strict;
use warnings;

use HTTP::Cookies;

use Digest::MD5 qw(md5 md5_hex md5_base64);
use Digest::SHA qw(sha1 sha1_hex sha1_base64 hmac_sha1 hmac_sha1_hex hmac_sha1_base64);

use POSIX qw(strftime);

my $lwpua = LWP::UserAgent->new;

my $uagent = "Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.0.6) Gecko/20060728 Firefox/1.5.0.6";
my @header = ('Referer' => 'https://api.twitter.com/',
             'User-Agent' => $uagent,
             'Authorization' => 'OAuth');

# build the signature base
my $post_url = "https://api.twitter.com/oauth/request_token";
my $callback_url = "http://flusso1.wolfpac.net/tweext/twitter.php";
my $nonce = md5_base64(localtime()).md5_base64(localtime());
my $timestamp = strftime('%s', localtime);
my $method = "HMAC-SHA1";
my $version = "1.0";
my $consumer_key = "fy13RaNud7FQl1AVafzq9g";
my $consumer_secret = "3FHgsf5ychPlLPaDF7f1RRjJthU5rPMCPa9kpJbbpK4";

my $callback_urlenc = &urlencode($callback_url);
my $post_urlenc = &urlencode($post_url);

my $oauth_data = "oauth_callback=$callback_urlenc&oauth_consumer_key=$consumer_key&oauth_nonce=$nonce&oauth_signature_method=$method&oauth_timestamp=$timestamp&oauth_version=$version";
my $oauth_dataenc = &urlencode($oauth_data);

my $sign_base = "POST&".$post_urlenc."&".$oauth_dataenc;
my $sign_key = $consumer_secret."&";

# oauth signature
my $oauth_sign = hmac_sha1_base64($sign_base, $sign_key)."=";

# post oauth request
my $response = $lwpua->post($post_url,
                        ['oauth_callback' => $callback_url,
                         'oauth_consumer_key' => $consumer_key,
                         'oauth_nonce' => $nonce,
                         'oauth_signature_method' => $method,
                         'oauth_signature' => $oauth_sign,
                         'oauth_timestamp' => $timestamp,
                         'oauth_version' => $version], @header);
my $form_data = $response->content;

$form_data =~ s/\n//g;
$form_data =~ /^oauth_token=(.*?)&oauth_token_secret=(.*?)&oauth_callback_confirmed=(.*?)\s*$/gi;

my $oauth_token = $1;
my $oauth_secret = $2;
my $oauth_confirm = $3;

print "$oauth_token|$oauth_secret|$oauth_confirm\n";
print "done!";

sub urlencode
{
  my ($url) = @_;

  $url =~ s/([^A-Za-z0-9_.-])/sprintf("%%%02X", ord($1))/seg;
  return $url;
}


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