Help with add_part in HTTP::Message for making Batch HTTP requests for Google API

[Anonymous Monk]

The Google Batch Indexing API allows batches of HTTP requests in a format specified at: Batch Indexing Example HTTP Request Batch Post request shows an example of using add_part to do this, however is lacking one level of data within the "part" added via add_part, basically it needs a set of headers w/o a (GET/POST request) followed by the content of the actual HTTP request for the contained request Here's a "part":

Content-Type: application/http
Content-Transfer-Encoding: binary
Content-ID: <b29c5de2-0db4-490b-b421-6a51b598bd22+3>

POST /v3/urlNotifications:publish [3]
Content-Type: application/json
accept: application/json
content-length: 58

{ "url": "http://example.com/jobs/43", "type": "URL_DELETED" }

I can get add_part to add the 2nd part

POST /v3/urlNotifications:publish [3]
Content-Type: application/json
accept: application/json
content-length: 58

{ "url": "http://example.com/jobs/43", "type": "URL_DELETED" }

But not the headers above that via add_part in HTTP::Message

Content-Type: application/http
Content-Transfer-Encoding: binary
Content-ID: <b29c5de2-0db4-490b-b421-6a51b598bd22+3>

Here's example code that generates a request minus those extra set of headers

#!/usr/bin/env perl
use strictures;
use HTTP::Request::Common;
use JSON;
use URI;

  my $request1 = POST "/v3/urlNotifications:publish",
    Content_Type => 'application/json',
    Accept => 'application/json',
    Content_ID => "1",
    Content => encode_json({ url => 'http://example.com/1', type => "U
+RL_UPDATED" } );

    my $request2 = POST "/v3/urlNotifications:publish",
    Content_Type => 'application/json',
    Accept => 'application/json',
    Content_ID => "2",
    Content => encode_json({ url => "http://example.com/2", type => "U
+RL_UPDATED" } );


my $endpoint = URI->new("https://indexing.googleapis.com/batch");
my $base_request = POST $endpoint,
    Authorization => "Bearer TOKEN",
    Content_Type => 'multipart/mixed; boundary=xYzZY123';

$base_request->add_part( $request1, $request2 );

print $base_request->as_string;

Outputs:

Authorization: Bearer TOKEN
Content-Length: 0
Content-Type: multipart/mixed; boundary=xYzZY123

--xYzZY123
POST /v3/urlNotifications:publish
Accept: application/json
Content-Length: 51
Content-Type: application/json
Content-ID: 1

{"url":"http://example.com/1","type":"URL_UPDATED"}
--xYzZY123
POST /v3/urlNotifications:publish
Accept: application/json
Content-Length: 51
Content-Type: application/json
Content-ID: 2

{"url":"http://example.com/2","type":"URL_UPDATED"}
--xYzZY123-

But need a way to add the additional headers of to each part

Content-Type: application/http
Content-Transfer-Encoding: binary
Content-ID: <b29c5de2-0db4-490b-b421-6a51b598bd22+2>

Overriding HTTP::Message's _part_class at: Link to code looks potentially promising, but not quite sure how to best accomplish. I think if I could force those add_part's to become a new class I define, I could override that classes as_string method to include the additional headers needed. I could use some pointers on how to accomplish that --or-- another suggested approach. Another thing I tried was composing the part of 2 HTTP::Requests -- first w/o a METHOD & URL, and those headers with content composed of a 2nd HTTP::Request. That was close to working but I got an extra line and - since I didn't specify a METHOD or URL for the upper (partial request) Any tips to help me get past this final hurdle would be most appreciated! Sample batch indexing format below:

POST /batch HTTP/1.1
Host: indexing.googleapis.com
Content-Length: content_length
Content-Type: multipart/mixed; boundary="===============73308459742167
+40156=="
Authorization: Bearer oauth2_token

--===============7330845974216740156==
Content-Type: application/http
Content-Transfer-Encoding: binary
Content-ID: <b29c5de2-0db4-490b-b421-6a51b598bd22+2>

POST /v3/urlNotifications:publish [1]
Content-Type: application/json
accept: application/json
content-length: 58

{ "url": "http://example.com/jobs/42", "type": "URL_UPDATED" }
--===============7330845974216740156==
Content-Type: application/http
Content-Transfer-Encoding: binary
Content-ID: <b29c5de2-0db4-490b-b421-6a51b598bd22+1>

POST /v3/urlNotifications:publish [2]
Content-Type: application/json
accept: application/json
content-length: 75

{ "url": "http://example.com/widgets/1", "type": "URL_UPDATED" }
--===============7330845974216740156==
Content-Type: application/http
Content-Transfer-Encoding: binary
Content-ID: <b29c5de2-0db4-490b-b421-6a51b598bd22+3>

POST /v3/urlNotifications:publish [3]
Content-Type: application/json
accept: application/json
content-length: 58

{ "url": "http://example.com/jobs/43", "type": "URL_DELETED" }
--===============7330845974216740156==

[Anonymous Monk]

Here's example code that generates a request minus those extra set of headers

Ugh. Its a request within a request within a request. Its not hard. You dont have to involve LWP until you have to involve it.

This is almost but not quite it

#!/usr/bin/perl --
use strict;
use warnings;
use JSON;
use LWP;

my $endpoint = URI->new("https://indexing.googleapis.com/batch");
use HTTP::Request::Common();
my $base_request = HTTP::Request::Common::POST( 
    $endpoint, 
    Authorization => "Bearer TOKEN",
    Content_Type => 'multipart/mixed',
);
$base_request->add_part( 
    BlaFoo({ url => 'http://example.com/1', type => "URL_UPDATED" }),
    BlaFoo({ url => "http://example.com/2", type => "URL_UPDATED" })
);

print $base_request->as_string;


exit 0 ;

sub BlaFoo {
    return SnaFoo(
        POST => "/v3/urlNotifications:publish",  ## todo?
        Content_Type => 'application/json',
        Accept => 'application/json',
        Content => encode_json( shift )
    );
}

sub SnaFoo {
    my $req = HTTP::Message->new;
    my $content;
    $content = shift if @_ and ref $_[0];
    my($k, $v);
    while (($k,$v) = splice(@_, 0, 2)) {
        if (lc($k) eq 'content') {
            $content = $v;
        } else {
            $req->push_header($k, $v);
        }
    }
    $req->header('Content-Length' => length($content)) unless ref($con
+tent);
    $req->content($content);
    
    $req = HTTP::Message->new( undef, $req->as_string );
    
    $req->header( 'Content-Type' => 'application/http' );
    $req->header( 'Content-Transfer-Encoding' => 'binary' );
    $req->header( 'Content-ID' => '<b29c5de2-0db4-490b-b421-6a51b598bd
+22+2>' ); ## todo?
    
    return $req;
}
__END__