This brief guide explains 2 different reasons for wanting to send POST data with curl and how to do it. It is very handy to have the abililty to arbitrarily send POST data from a form to a script.
Sending POST data and placing the response into a variable
Many of my website clients want me to integrate their email newsletter program CoCoTalk throughout their sites.
CoCoTalk provides iframe code to stick on clients sites that automatically produces a form to sign up to the newsletter. But I use XHTML strict on my sites, so no iframes allowed.
The CoCoTalk iframe code and resulting HTML
XHTML strict replacement CoCoTalk code
cocotalk.php
This code gets the correct EmailAddress from the POST data and then creates a 2nd POST request to the CoCoTalk url. It mimics the settings and vars of the original CoCoTalk form.
Relaying POST data, allowing the script to redirect
You could add a hidden input variable to your forms and then based on that variable you can redirect the POST vars to a certain script.
Code for send-email.php
This simply acts as a POST relay or proxy that you can use to send off your POST results to multiple scripts.
Code for waiting.php
This actually processes the post (the send_email function).
TRUE to mark this as a new cookie "session". It will force libcurl to ignore all cookies it is about to load that are "session cookies" from the previous session. By default, libcurl always stores and loads all cookies, independent if they are session cookies are not. Session cookies are cookies without expiry date and they are meant to be alive and existing for this "session" only.
TRUE to fail silently if the HTTP code returned is greater than or equal to 400. The default behavior is to return the page normally, ignoring the code.
TRUE to attempt to retrieve the modification date of the remote document. You can then retrieve this value using the CURLINFO_FILETIME option with curl_getinfo().
TRUE to follow any "Location: " header that the server sends as part of the HTTP header (note this is recursive, PHP will follow as many "Location: " headers that it is sent, unless CURLOPT_MAXREDIRS is set).
TRUE to ignore any cURL function that causes a signal to be sent to the PHP process. This is turned on by default in multi-threaded SAPIs so timeout options can still be used.
FALSE to stop cURL from verifying the peer's certificate. Alternate certificates to verify against can be specified with the CURLOPT_CAINFO option or a certificate directory can be specified with the CURLOPT_CAPATH option.
TRUE to use ASCII mode for FTP transfers. For LDAP, it retrieves data in plain text instead of HTML. On Windows systems, it will not set STDOUT to binary mode.
Either CURLCLOSEPOLICY_LEAST_RECENTLY_USED or CURLCLOSEPOLICY_OLDEST. There are three other CURLCLOSEPOLICY_ constants, but cURL does not support them yet.
_HTTP_VERSION_NONE (default, lets CURL decide which version to use), CURL_HTTP_VERSION_1_0 (forces HTTP/1.0), or CURL_HTTP_VERSION_1_1 (forces HTTP/1.1).
The HTTP authentication method(s) to use. The options are: CURLAUTH_BASIC, CURLAUTH_DIGEST, CURLAUTH_GSSNEGOTIATE, CURLAUTH_NTLM, CURLAUTH_ANY, and CURLAUTH_ANYSAFE.
The transfer speed, in bytes per second, that the transfer should be below during CURLOPT_LOW_SPEED_TIME seconds for PHP to consider the transfer too slow and abort.
The maximum amount of persistent connections that are allowed. When the limit is reached, CURLOPT_CLOSEPOLICY is used to determine which connection to close.
The HTTP authentication method(s) to use for the proxy connection. Use the same bitmasks as described in CURLOPT_HTTPAUTH. For proxy authentication, only CURLAUTH_BASIC and CURLAUTH_NTLM are currently supported.
1 to check the existence of a common name in the SSL peer certificate. 2 to check the existence of a common name and also verify that it matches the hostname provided.
How CURLOPT_TIMEVALUE is treated. Use CURL_TIMECOND_IFMODSINCE to return the page only if it has been modified since the time specified in CURLOPT_TIMEVALUE. If it hasn't been modified, a "304 Not Modified" header will be returned assuming CURLOPT_HEADER is TRUE . Use CURL_TIMECOND_ISUNMODSINCE for the reverse effect. CURL_TIMECOND_IFMODSINCE is the default. Added in PHP 5.1.0.
The name of a file holding one or more certificates to verify the peer with. This only makes sense when used in combination with CURLOPT_SSL_VERIFYPEER.
A custom request method to use instead of "GET" or "HEAD" when doing a HTTP request. This is useful for doing "DELETE" or other, more obscure HTTP requests. Valid values are things like "GET", "POST", "CONNECT" and so on; i.e. Do not enter a whole HTTP request line here. For instance, entering "GET /index.html HTTP/1.0rnrn" would be incorrect.
The contents of the "Accept-Encoding: " header. This enables decoding of the response. Supported encodings are "identity", "deflate", and "gzip". If an empty string, "", is set, a header containing all supported encoding types is sent.
The value which will be used to get the IP address to use for the FTP "POST" instruction. The "POST" instruction tells the remote server to connect to our specified IP address. The string may be a plain IP address, a hostname, a network interface name (under Unix), or just a plain '-' to use the systems default IP address.
The KRB4 (Kerberos 4) security level. Any of the following values (in order from least to most powerful) are valid: "clear", "safe", "confidential", "private".. If the string does not match one of these, "private" is used. Setting this option to NULL will disable KRB4 security. Currently KRB4 security only works with FTP transactions.
Range(s) of data to retrieve in the format "X-Y" where X or Y are optional. HTTP transfers also support several intervals, separated with commas in the format "X-Y,N-M".
The name of a callback function where the callback function takes two parameters. The first is the cURL resource, the second is a string with the header data to be written. Using this callback function, it becomes your responsibility to write the header data. Return the number of bytes written.
The name of a callback function where the callback function takes three parameters. The first is the cURL resource, the second is a string containing a password prompt, and the third is the maximum password length. Return the string containing the password.
The name of a callback function where the callback function takes two parameters. The first is the cURL resource, and the second is a string with the data to be read. Using this callback function, it becomes your responsibility to read the data. Return the number of bytes read. Return 0 to signal EOF.
The name of a callback function where the callback function takes two parameters. The first is the cURL resource, and the second is a string with the data to be written. Using this callback function, it becomes your responsibility to write the data. Must return the exact number of bytes written or this will fail.
Predefined CURL Constants
The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.
