Improving the twit perl script

As I spent some time on twit.pl v0.2.0, I also tried to improve on the Perl template for new scripts.

New Perl that I learned
Today, I'll try to explain the new concepts first and then show the code.

• "$0": This is dollar-zero. It is a special Perl variable to indicate the name of the file containing the perl script being executed
• The x operator repeats a string pattern.
  print "*" x 10; and print "**********"; are equivalent
• defined will return false if a variable is undef and true if it has a value.
• @ARGV is a reserved Perl array that contains the list of arguments passed on the command line.
  Help if (@ARGV == 0); will call the Help subroutine if the list of arguments is empty, i.e. if you just type "perl twit.pl" at the command line.
  Note that checking @ARGV must be performed before the call to GetOptions which will empty the argument list.
• You can tell the GetOption procedure to directly call a subroutine when a specific argument is passed at the command line. See for example "version" => \&Version. When -v or --version is added after the script name, you will see the version number of the script and exit the program.

twit_0_2_0.pl
To use version 0.2.0, you have to add -t (for twitter), -i (for identica) or -a (for both, also works if you choose -t -i) to the command line.

view plainprint?

1. #!/usr/bin/perl  
2. use 5.10.0;         # To be able to use "say" function  
3. use strict;         # Pragma to add restrictions to Perl rules  
4. use warnings;       # Pragma to add warnings at compile and run-time  
5. use Getopt::Long;   # To parse the command line  
6. use Net::Twitter;   # API to twitter.com and identi.ca  
7.   
8. my $PROG_NAME = $0; # $0 contains the name of the file containing the Perl script being executed  
9. my $VERSION   = "v0.2.0";  
10. my $VersionDate = "February 21st 2009";  
11.   
12. # ------------------------------------------------------------------------------  
13. # Name    : Help  
14. # Comment : displays list of available options  
15. # Input   : no argument to command line or "-h" or "--help"  
16. # Output  : help screen and exit program  
17. # ------------------------------------------------------------------------------  
18. sub Help {  
19.     print "   
20.     Usage:  
21.         perl $PROG_NAME [-options]          
22.   
23.     Options:  
24.      -a, --all      : send message to all supported macroblogging sites  
25.      -f, --file     : file containing the login information for each site  
26.      -h, --help     : this help screen  
27.      -i, --identica : send message to identi.ca  
28.      -s, --status   : status (message) to send  
29.      -t, --twitter  : send message to twitter.com  
30.      -v, --version  : displays version information  
31.               
32.     $PROG_NAME help  
33.     ";  
34.     print "-" x (length ($PROG_NAME) + 5);  
35.     print "  
36.     $PROG_NAME sends a status update to either twitter.com or identi.ca (or both) from the command line.  
37.     If -t is specified (for example), it will send the update to twitter.com.  
38.     If -a is passed, then your status on both twitter and identica will be updated.  
39.   
40.     Format of login files  
41.     ---------------------  
42.     $PROG_NAME will first try to find \"twit.txt\" located in the current directory.  
43.     You can also use the --file option to tell $PROG_NAME where to find your login information.  
44.      - Lines starting with '#' are comments and will be ignored by the script  
45.      - The last line starting with \"Twitter\" will be parsed for username and password.   
46.        Each of these fields must be separated by a semi-column ':'  
47.      - Same thing with \"Identica\"  
48.           
49.     Examples:  
50.     ---------  
51.      - perl twit.pl -s \"Using Padre on Linux\" -f \"~/secretstuff/mytwitterpassword.txt\" -a  
52.         Updates both twitter and identica status with login info from specified file  
53.      - perl twit.pl -s \"This is Vistaaaaaa\" -i  
54.         Updates identica status only  
55.   
56.     $PROG_NAME uses the following modules:  
57.      - Getopt::Long  
58.      - Net::Twitter  
59.     ";  
60.     exit;  
61. } # End of Help  
62.   
63. # ------------------------------------------------------------------------------  
64. # Name    : version  
65. # Comment : displays script's version number  
66. # Input   : --  
67. # Output  : version number screen and exit program  
68. # ------------------------------------------------------------------------------  
69. sub Version {  
70.     print "  
71.     $PROG_NAME version: $VERSION  
72.     Date  : $VersionDate  
73.     Author: dlp  
74.           
75.     Get the latest version from here:  
76.     http://sites.google.com/site/damienlearnsperl/DLP-scripts  
77.     ";  
78.     exit;  
79. } # end of Version  
80.   
81. # ------------------------------------------------------------------------------  
82. # Name    : CreateObject  
83. # Comment : Creates and returns an instance of the Net::Twitter class  
84. # Input   : - Input string with value  
85. #               "twitter" -> twitter.com instance  
86. #               "identica" -> identi.ca instance  
87. #               all other values return an error  
88. #           - Hash with "UserName" and "Password"  
89. # Output  : Object newly created or 0 if error  
90. # ------------------------------------------------------------------------------  
91. sub CreateObject {  
92.     my $SiteInstance = 0;  
93.     my $NameString = shift;  
94.     my %Login = @_;  
95.   
96.     $NameString =~ tr/A-Z/a-z/;  
97.     if ($NameString eq "twitter") {  
98.         $SiteInstance = Net::Twitter->new(username => $Login{"UserName"}, password => $Login{"Password"});  
99.     }  
100.     elsif ($NameString eq "identica") {  
101.         $SiteInstance = Net::Twitter->new(identica => 1, username => $Login{"UserName"}, password => $Login{"Password"});  
102.     }  
103.     return $SiteInstance;  
104. } # End of CreateObject  
105.   
106. # ------------------------------------------------------------------------------  
107. # Name    : SendUpdate  
108. # Comment : Sends update to Twitter object  
109. # Input   : - Net::Twitter object  
110. #           - message string  
111. # Output  : string "OK" if successful update, string "FAIL" otherwise  
112. # ------------------------------------------------------------------------------  
113. sub SendUpdate {  
114.     my $Site = shift;  
115.     my $Message = shift;  
116.     my $SiteName = ($Site->{identica})?"identi.ca":"twitter.com";  
117.   
118.     #There's a hard limit on the size of twits for both twitter and identica  
119.     if (!defined $Message) {  
120.         return "$SiteName update: FAILED (no message)";  
121.     }  
122.     if (length $Message > 140) {  
123.         return "$SiteName update: FAILED (message over 140 characters)";  
124.     }  
125.   
126.     if ($Site->update($Message)) {  
127.         return "$SiteName update: OK";  
128.     }  
129.     else {  
130.         return "$SiteName update: FAIL";  
131.     }  
132. } #End of SendUpdate  
133.   
134. # ------------------------------------------------------------------------------  
135. # Name    : SendMessage  
136. # Comment : Sends message to chosen macroblogging site  
137. # Input   : $_[0] = Input string with value  
138. #               "twitter" -> twitter.com instance  
139. #               "identica" -> identi.ca instance  
140. #           $_[1] = Message string to be sent  
141. #           $_[2] = Hash with "UserName" and "Password" elements  
142. # Output  : Return string: "Error" if couldn't create object or string from SendUpdate  
143. # ------------------------------------------------------------------------------  
144. sub SendMessage {  
145.     my $ReturnString;  
146.     my $Instance;  
147.     my ($SiteName, $Message, %Login) = @_;  
148.   
149.     $Instance = CreateObject($SiteName, %Login);  
150.     if ($Instance) {  
151.         $ReturnString = SendUpdate($Instance, $Message);  
152.     }  
153.     else {  
154.         $ReturnString = "Error with $SiteName creation process";  
155.     }  
156.     return $ReturnString;  
157. } #End of SendMessage  
158.   
159. # ------------------------------------------------------------------------------  
160. # Main  
161. # ------------------------------------------------------------------------------  
162. my $Status;  
163. my $PasswordFile;  
164. my %TwitLogin;  
165. my %IdenticaLogin;  
166. my $TwitterUse;  # 1-> send to twitter, 0 -> do not send  
167. my $IdenticaUse; # 1-> send to identica, 0 -> do not send  
168.   
169. Help if (@ARGV == 0);  
170.   
171. #Parse command line arguments  
172. GetOptions ("all" => sub {$TwitterUse = 1; $IdenticaUse = 1},  
173.             "status=s" => \$Status,  
174.             "file=s" => \$PasswordFile,  
175.             "help" => \&Help,  
176.             "identica" => \$IdenticaUse,  
177.             "twitter" => \$TwitterUse,  
178.             "version" => \&Version);  
179.   
180. # Read Password file passed as argument or twit.txt by default  
181. $PasswordFile = "twit.txt" unless ($PasswordFile);  
182. open(LOGINFILE, $PasswordFile) or die "Cannot open \"$PasswordFile\" file: $!\n";  
183. while (<loginfile>) {  
184.     my $line = $_;  
185.     my $PlaceHolder;  
186.   
187.     chomp $line;    # Remove trailing newline character  
188.     next if ($line =~ m/^#/);       # Ignore lines starting with '#'  
189.     if ($line =~ m/^twitter/i) {    # /^ indicates the beginning of the line  
190.         ($PlaceHolder, $TwitLogin{"UserName"}, $TwitLogin{"Password"}) = split (/:/, $line);  
191.     }  
192.     if ($line =~ m/^identica/i) {   # /i to ignore alphabetic case  
193.         ($PlaceHolder, $IdenticaLogin{"UserName"}, $IdenticaLogin{"Password"}) = split (/:/, $line);  
194.     }  
195. }  
196. close (LOGINFILE);  
197.   
198. say SendMessage("Twitter", $Status, %TwitLogin) if ($TwitterUse);  
199. say SendMessage("Identica", $Status, %IdenticaLogin) if ($IdenticaUse);  
200. Help if (!defined ($TwitterUse) && !defined ($IdenticaUse));  
201.   
202. __END__  
203. To do:  
204. - Use POD format for comments  
205. - Simple GUI interface (1 text box + 1 check box for each Twitter and Identi.ca + 1 "Send" button)  
206. - Create executable file for standalone use without need of a Perl interpreter  
207.   
208. History:  
209. ...  
210. v0.2.0 (2009/02/21): Added --twitter (-t) and --identica (-i) command line options to select site for updates  
211.                      Added --help (-h) and --version (-v) command line options  
212.                      Added undefined argument check for $Message in SendUpdate().  
213. </loginfile>  

#!/usr/bin/perl
use 5.10.0;         # To be able to use "say" function
use strict;         # Pragma to add restrictions to Perl rules
use warnings;       # Pragma to add warnings at compile and run-time
use Getopt::Long;   # To parse the command line
use Net::Twitter;   # API to twitter.com and identi.ca

my $PROG_NAME = $0; # $0 contains the name of the file containing the Perl script being executed
my $VERSION   = "v0.2.0";
my $VersionDate = "February 21st 2009";

# ------------------------------------------------------------------------------
# Name    : Help
# Comment : displays list of available options
# Input   : no argument to command line or "-h" or "--help"
# Output  : help screen and exit program
# ------------------------------------------------------------------------------
sub Help {
    print " 
    Usage:
        perl $PROG_NAME [-options]        

    Options:
     -a, --all      : send message to all supported macroblogging sites
     -f, --file     : file containing the login information for each site
     -h, --help     : this help screen
     -i, --identica : send message to identi.ca
     -s, --status   : status (message) to send
     -t, --twitter  : send message to twitter.com
     -v, --version  : displays version information
            
    $PROG_NAME help
    ";
    print "-" x (length ($PROG_NAME) + 5);
    print "
    $PROG_NAME sends a status update to either twitter.com or identi.ca (or both) from the command line.
    If -t is specified (for example), it will send the update to twitter.com.
    If -a is passed, then your status on both twitter and identica will be updated.

    Format of login files
    ---------------------
    $PROG_NAME will first try to find \"twit.txt\" located in the current directory.
    You can also use the --file option to tell $PROG_NAME where to find your login information.
     - Lines starting with '#' are comments and will be ignored by the script
     - The last line starting with \"Twitter\" will be parsed for username and password. 
       Each of these fields must be separated by a semi-column ':'
     - Same thing with \"Identica\"
        
    Examples:
    ---------
     - perl twit.pl -s \"Using Padre on Linux\" -f \"~/secretstuff/mytwitterpassword.txt\" -a
        Updates both twitter and identica status with login info from specified file
     - perl twit.pl -s \"This is Vistaaaaaa\" -i
        Updates identica status only

    $PROG_NAME uses the following modules:
     - Getopt::Long
     - Net::Twitter
    ";
    exit;
} # End of Help

# ------------------------------------------------------------------------------
# Name    : version
# Comment : displays script's version number
# Input   : --
# Output  : version number screen and exit program
# ------------------------------------------------------------------------------
sub Version {
    print "
    $PROG_NAME version: $VERSION
    Date  : $VersionDate
    Author: dlp
        
    Get the latest version from here:
    http://sites.google.com/site/damienlearnsperl/DLP-scripts
    ";
    exit;
} # end of Version

# ------------------------------------------------------------------------------
# Name    : CreateObject
# Comment : Creates and returns an instance of the Net::Twitter class
# Input   : - Input string with value
#               "twitter" -> twitter.com instance
#               "identica" -> identi.ca instance
#               all other values return an error
#           - Hash with "UserName" and "Password"
# Output  : Object newly created or 0 if error
# ------------------------------------------------------------------------------
sub CreateObject {
    my $SiteInstance = 0;
    my $NameString = shift;
    my %Login = @_;

    $NameString =~ tr/A-Z/a-z/;
    if ($NameString eq "twitter") {
        $SiteInstance = Net::Twitter->new(username => $Login{"UserName"}, password => $Login{"Password"});
    }
    elsif ($NameString eq "identica") {
        $SiteInstance = Net::Twitter->new(identica => 1, username => $Login{"UserName"}, password => $Login{"Password"});
    }
    return $SiteInstance;
} # End of CreateObject

# ------------------------------------------------------------------------------
# Name    : SendUpdate
# Comment : Sends update to Twitter object
# Input   : - Net::Twitter object
#           - message string
# Output  : string "OK" if successful update, string "FAIL" otherwise
# ------------------------------------------------------------------------------
sub SendUpdate {
    my $Site = shift;
    my $Message = shift;
    my $SiteName = ($Site->{identica})?"identi.ca":"twitter.com";

    #There's a hard limit on the size of twits for both twitter and identica
    if (!defined $Message) {
        return "$SiteName update: FAILED (no message)";
    }
    if (length $Message > 140) {
        return "$SiteName update: FAILED (message over 140 characters)";
    }

    if ($Site->update($Message)) {
        return "$SiteName update: OK";
    }
    else {
        return "$SiteName update: FAIL";
    }
} #End of SendUpdate

# ------------------------------------------------------------------------------
# Name    : SendMessage
# Comment : Sends message to chosen macroblogging site
# Input   : $_[0] = Input string with value
#               "twitter" -> twitter.com instance
#               "identica" -> identi.ca instance
#           $_[1] = Message string to be sent
#           $_[2] = Hash with "UserName" and "Password" elements
# Output  : Return string: "Error" if couldn't create object or string from SendUpdate
# ------------------------------------------------------------------------------
sub SendMessage {
    my $ReturnString;
    my $Instance;
    my ($SiteName, $Message, %Login) = @_;

    $Instance = CreateObject($SiteName, %Login);
    if ($Instance) {
        $ReturnString = SendUpdate($Instance, $Message);
    }
    else {
        $ReturnString = "Error with $SiteName creation process";
    }
    return $ReturnString;
} #End of SendMessage

# ------------------------------------------------------------------------------
# Main
# ------------------------------------------------------------------------------
my $Status;
my $PasswordFile;
my %TwitLogin;
my %IdenticaLogin;
my $TwitterUse;  # 1-> send to twitter, 0 -> do not send
my $IdenticaUse; # 1-> send to identica, 0 -> do not send

Help if (@ARGV == 0);

#Parse command line arguments
GetOptions ("all" => sub {$TwitterUse = 1; $IdenticaUse = 1},
            "status=s" => \$Status,
            "file=s" => \$PasswordFile,
            "help" => \&Help,
            "identica" => \$IdenticaUse,
            "twitter" => \$TwitterUse,
            "version" => \&Version);

# Read Password file passed as argument or twit.txt by default
$PasswordFile = "twit.txt" unless ($PasswordFile);
open(LOGINFILE, $PasswordFile) or die "Cannot open \"$PasswordFile\" file: $!\n";
while () {
    my $line = $_;
    my $PlaceHolder;

    chomp $line;    # Remove trailing newline character
    next if ($line =~ m/^#/);       # Ignore lines starting with '#'
    if ($line =~ m/^twitter/i) {    # /^ indicates the beginning of the line
        ($PlaceHolder, $TwitLogin{"UserName"}, $TwitLogin{"Password"}) = split (/:/, $line);
    }
    if ($line =~ m/^identica/i) {   # /i to ignore alphabetic case
        ($PlaceHolder, $IdenticaLogin{"UserName"}, $IdenticaLogin{"Password"}) = split (/:/, $line);
    }
}
close (LOGINFILE);

say SendMessage("Twitter", $Status, %TwitLogin) if ($TwitterUse);
say SendMessage("Identica", $Status, %IdenticaLogin) if ($IdenticaUse);
Help if (!defined ($TwitterUse) && !defined ($IdenticaUse));

__END__
To do:
- Use POD format for comments
- Simple GUI interface (1 text box + 1 check box for each Twitter and Identi.ca + 1 "Send" button)
- Create executable file for standalone use without need of a Perl interpreter

History:
...
v0.2.0 (2009/02/21): Added --twitter (-t) and --identica (-i) command line options to select site for updates
                     Added --help (-h) and --version (-v) command line options
                     Added undefined argument check for $Message in SendUpdate().

It is getting a bit long to post the whole script on this blog. You can still find the latest version to download here.
There are better ways to include help and comments in code. I will talk about POD soon.

Larry Wall quote of the day:
"We all agree on the necessity of compromise. We just can't agree on when it's necessary to compromise."

Possible next posts:

• Perl template - Part II: Adding Help and Version procedures
  
• Perl help resources
• Improving on twit.pl: Graphical User interface
  
• POD
• Install Google Analytics on your Blogger blog and stats for DLP