Autarchy of the Private Cave » HTTP_Client

Allow posting duplicate form-name entries with different values

Bogdan — Wed, 06 Sep 2006 09:04:41 +0000

Sometimes, writing automatic HTML forms processors, you need to post several values with the same name of the form field, e.g.:
collection_gene = str_chrom_name
collection_gene = gene_stable_id

This is against the RFC on form fields design and submitting, but this approach is used – for example, by Ensembl. I spent some time to figure out how to make HTTP_Client and HTTP_Request submit multiple ‘name-value’ pairs instead of one (the latest defined, which overrides the previous). The solution is extremely simple:

/*
allow posting duplicate form-name
entries with different values
*/
$params['useBrackets'] = false;
$req = &new HTTP_Client($params, $headers);

After setting ‘useBrackets’ parameter to ‘false’, HTTP_Client/HTTP_Request do post multiple lines as you would want it.

Hope this saves you some time.

Avoiding out of memory fatal error when using HTTP_Client or HTTP_Request

Bogdan — Wed, 06 Sep 2006 08:58:29 +0000

If you fetch large amounts of data (e.g. over 2MB per request) using HTTP_Client (or HTTP_request), you may get “out of memory” fatal errors, especially if:

memory_limit is set to default 8M, and
you process multiple pages using single non-reset instance of HTTP_Client object.

This problem can manifest itself by producing fatal error after a couple of cycles of successful page retrieval – but always, if run with the same parameters, after some constant or only slightly variable number of cycles.

In my case the problem was that HTTP_Request (a dependancy of HTTP_Client) was holding in memory all the previously fetched pages of the current session (the ‘history’ feature). To force HTTP_Request to hold only the most recent page, you need to ‘disable’ history after creating the HTTP_Client or HTTP_Request object instance:

$req = &new HTTP_Client($params, $headers);
// disable history to save memory
$req->enableHistory(false);

Hope this helps you.

Using PEAR HTTP_Client or HTTP_Request with HTTP proxy

Bogdan — Wed, 06 Sep 2006 08:00:46 +0000

If you happen to write PHP script, which uses either HTTP_Client or its dependancy HTTP_Request from PEAR, and the script is supposed to work through the HTTP proxy – here are the sample settings you need:

$params['proxy_user'] = 'proxy_username';
$params['proxy_pass'] = 'proxy_password';
$params['proxy_host'] = 'proxy_hostname_or_ip';
$params['proxy_port'] = 8080; // 3128, ...
// I assume $headers were set somewhere else
$req = &new HTTP_Client($params, $headers);

If your proxy does not need authorization – just drop the proxy_user and proxy_pass parameters.