Added currency converter programs

Author: rai-gaurav

README.md

@@ -8,7 +8,7 @@
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-![](https://img.shields.io/github/repo-size/rai-gaurav/Data-Structures-and-Algorithms-Perl.svg?label=Repo%20size&style=flat) 
+![](https://img.shields.io/github/repo-size/rai-gaurav/Data-Structures-and-Algorithms-Perl.svg?label=Repo%20size&style=flat)
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@@ -23,17 +23,17 @@ Hopefully will work on older version too (as old as 5.10) and across diferent OS
 
 | Backtracking     | Status    |
 | ---------------- | --------- |
-| 8 Queens Problem | 
+| 8 Queens Problem |
 | Combinations     | Completed |
 | Permutations     | Completed |
-| Sudoku           | 
+| Sudoku           |
 
-| Blockchain | Status |
-| ---------- | ------ |
+| Blockchain                | Status    |
+| ------------------------- | --------- |
 | chinese_remainder_theorem | Completed |
 
-| Client_Server | Status |
-| ------------- | ------ |
+| Client_Server         | Status    |
+| --------------------- | --------- |
 | Client Server example | Completed |
 
 | Compression     | Status |
@@ -129,9 +129,12 @@ Hopefully will work on older version too (as old as 5.10) and across diferent OS
 | Problem 7     | Completed |
 | Problem 8     | Completed |
 
-| Web Programming | Status    |
-| --------------- | --------- |
-| Catalyst        |
-| Dancer2         |
-| Mojolicious     |
-| Web Crawling    |
+| Web Programming    | Status    |
+| ------------------ | --------- |
+| Catalyst           |
+| Dancer2            |
+| Mojolicious        |
+| Web Crawling       |
+| Currency Converter | Completed |
+| Weather            |
+| Stock Price        |

web_programming/currency_converter/currency_converter_lwp.pl

@@ -0,0 +1,76 @@
+#!/usr/bin/env perl
+# There are many api available to get conversion rates. Some free with limitations.
+# You can use any of them but there is less chance that any of them will be real time.
+# Some of them are -
+#   https://www.amdoren.com/currency-api/
+#   https://fixer.io/
+#   https://currencylayer.com/
+#   https://www.exchangerate-api.com/docs/perl-currency-api
+
+# There are also different client lib available to perform these request in Perl.
+# Current used one - https://metacpan.org/pod/LWP::UserAgent
+
+use strict;
+use warnings;
+use LWP::UserAgent;
+use URI;
+use IO::Socket::SSL;
+use JSON;
+use Carp;
+
+# This will return the fingerprint of the given hostname
+sub get_fingerprint {
+    my ($dst) = @_;
+    my $client = IO::Socket::SSL->new(
+        PeerAddr => $dst,
+        PeerPort => 443,
+
+        # certificate cannot be validated the normal way, so we need to
+        # disable validation this one time in the hope that there is
+        # currently no man in the middle attack
+        SSL_verify_mode => 0,
+    ) or croak "connect failed";
+    my $fp = $client->get_fingerprint;
+    return $fp;
+}
+
+sub convert_currency {
+    my ($ua, $parameters) = @_;
+
+    my $url = URI->new("https://www.amdoren.com/api/currency.php");
+    $url->query_form(%{$parameters});
+
+    my $response = $ua->get($url);
+    if ($response->is_success) {
+        my $message       = $response->decoded_content;
+        my $json_response = from_json($message);
+        print "\n"
+            . $parameters->{'amount'} . " "
+            . $parameters->{'from'} . " = "
+            . $json_response->{'amount'} . " "
+            . $parameters->{'to'};
+    }
+    else {
+        croak $response->status_line;
+    }
+}
+
+sub main {
+
+    # This server certificate cannot be properly validated by normal means hence,
+    # we are getting fingerprint and passing that in LWP options.
+    # This step is not needed if we have proper server certificate.
+    # Reference - https://stackoverflow.com/a/35078145/2001559
+    my $fp = get_fingerprint("www.amdoren.com");
+    my $ua = LWP::UserAgent->new(ssl_opts => {SSL_fingerprint => $fp});
+    $ua->show_progress(1);
+
+    # Add your API key here or in your shell environment and remove this line
+    local $ENV{"AMDOREN_API_KEY"} = "";
+
+    # Convert 10 USD to INR, API key will be taken from env variable
+    convert_currency($ua,
+        {"api_key" => $ENV{"AMDOREN_API_KEY"}, "from" => "USD", "to" => "INR", "amount" => 10});
+}
+
+main;

web_programming/currency_converter/currency_converter_mojo.pl

@@ -0,0 +1,52 @@
+#!/usr/bin/env perl
+# There are many api available to get conversion rates. Some free with limitations.
+# You can use any of them but there is less chance that any of them will be real time.
+# Some of them are -
+#   https://www.amdoren.com/currency-api/
+#   https://fixer.io/
+#   https://currencylayer.com/
+#   https://www.exchangerate-api.com/docs/perl-currency-api
+
+# There are also different client lib available to perform these request in Perl.
+# Current used one - https://metacpan.org/pod/Mojo::UserAgent
+
+use strict;
+use warnings;
+use Mojo::UserAgent;
+
+sub convert_currency {
+    my ($ua, $parameters) = @_;
+
+    my $url = "https://www.amdoren.com/api/currency.php";
+
+    # This server certificate cannot be properly validated by normal means hence,
+    # we are disabling TLS certificate verification.
+    # There are other ways also like this - https://stackoverflow.com/a/35208289/2001559
+    $ua->insecure(1);
+
+    my $response = $ua->get($url => form => $parameters)->result;
+    if ($response->is_success) {
+        my $message = $response->json;
+        print "\n"
+            . $parameters->{'amount'} . " "
+            . $parameters->{'from'} . " = "
+            . $message->{'amount'} . " "
+            . $parameters->{'to'};
+    }
+    elsif ($response->is_error) {
+        print $response->message;
+    }
+}
+
+sub main {
+    my $ua = Mojo::UserAgent->new();
+
+    # Add your API key here or in your shell environment and remove this line
+    local $ENV{"AMDOREN_API_KEY"} = "";
+
+    # Convert 10 USD to INR, API key will be taken from env variable
+    convert_currency($ua,
+        {"api_key" => $ENV{"AMDOREN_API_KEY"}, "from" => "USD", "to" => "INR", "amount" => 10});
+}
+
+main;