Some basic questions about cURL and PHP

PHP
1

Having some understanding problems with curl and some basic php coding problems implementing it.

PHP.net says curl_init() "Initializes a new session and return a cURL handle "

What is a new session in this context, and what is a handle? I think of cookies when I think of sessions. I var_dump’d curl_init and just got something like “resource(curl)”.

Why is the standard default variable to hold a curl_init() called $ch? I see it in most curl examples, but I don’t know what it stands for. I thought it might be short for curl handle - but I don’t know what curl handles are.

Can someone tell why the in_array function fails to see that ‘5’ is in the array?


	$errCodes=array(
		1 => 'CURLE_UNSUPPORTED_PROTOCOL',
		2 => 'CURLE_FAILED_INIT',
		3 => 'CURLE_URL_MALFORMAT',
		4 => 'CURLE_URL_MALFORMAT_USER',
		5 => 'CURLE_COULDNT_RESOLVE_PROXY',
		6 => 'CURLE_COULDNT_RESOLVE_HOST',
		7 => 'CURLE_COULDNT_CONNECT',
		8 => 'CURLE_FTP_WEIRD_SERVER_REPLY',
		9 => 'CURLE_REMOTE_ACCESS_DENIED',
		11 => 'CURLE_FTP_WEIRD_PASS_REPLY',
		13 => 'CURLE_FTP_WEIRD_PASV_REPLY',
		14 =>'CURLE_FTP_WEIRD_227_FORMAT',
		15 => 'CURLE_FTP_CANT_GET_HOST',
		17 => 'CURLE_FTP_COULDNT_SET_TYPE',
		18 => 'CURLE_PARTIAL_FILE',
		19 => 'CURLE_FTP_COULDNT_RETR_FILE',
		21 => 'CURLE_QUOTE_ERROR',
		22 => 'CURLE_HTTP_RETURNED_ERROR',
		23 => 'CURLE_WRITE_ERROR',
		25 => 'CURLE_UPLOAD_FAILED',
		26 => 'CURLE_READ_ERROR',
		27 => 'CURLE_OUT_OF_MEMORY',
		28 => 'CURLE_OPERATION_TIMEDOUT',
		30 => 'CURLE_FTP_PORT_FAILED',
		31 => 'CURLE_FTP_COULDNT_USE_REST',
		33 => 'CURLE_RANGE_ERROR',
		34 => 'CURLE_HTTP_POST_ERROR',
		35 => 'CURLE_SSL_CONNECT_ERROR',
		36 => 'CURLE_BAD_DOWNLOAD_RESUME',
		37 => 'CURLE_FILE_COULDNT_READ_FILE',
		38 => 'CURLE_LDAP_CANNOT_BIND',
		39 => 'CURLE_LDAP_SEARCH_FAILED',
		41 => 'CURLE_FUNCTION_NOT_FOUND',
		42 => 'CURLE_ABORTED_BY_CALLBACK',
		43 => 'CURLE_BAD_FUNCTION_ARGUMENT',
		45 => 'CURLE_INTERFACE_FAILED',
		47 => 'CURLE_TOO_MANY_REDIRECTS',
		48 => 'CURLE_UNKNOWN_TELNET_OPTION',
		49 => 'CURLE_TELNET_OPTION_SYNTAX',
		51 => 'CURLE_PEER_FAILED_VERIFICATION',
		52 => 'CURLE_GOT_NOTHING',
		53 => 'CURLE_SSL_ENGINE_NOTFOUND',
		54 => 'CURLE_SSL_ENGINE_SETFAILED',
		55 => 'CURLE_SEND_ERROR',
		56 => 'CURLE_RECV_ERROR',
		58 => 'CURLE_SSL_CERTPROBLEM',
		59 => 'CURLE_SSL_CIPHER',
		60 => 'CURLE_SSL_CACERT',
		61 => 'CURLE_BAD_CONTENT_ENCODING',
		62 => 'CURLE_LDAP_INVALID_URL',
		63 => 'CURLE_FILESIZE_EXCEEDED',
		64 => 'CURLE_USE_SSL_FAILED',
		65 => 'CURLE_SEND_FAIL_REWIND',
		66 => 'CURLE_SSL_ENGINE_INITFAILED',
		67 => 'CURLE_LOGIN_DENIED',
		68 => 'CURLE_TFTP_NOTFOUND',
		69 => 'CURLE_TFTP_PERM',
		70 => 'CURLE_REMOTE_DISK_FULL',
		71 => 'CURLE_TFTP_ILLEGAL',
		72 => 'CURLE_TFTP_UNKNOWNID',
		73 => 'CURLE_REMOTE_FILE_EXISTS',
		74 => 'CURLE_TFTP_NOSUCHUSER',
		75 => 'CURLE_CONV_FAILED',
		76 => 'CURLE_CONV_REQD',
		77 => 'CURLE_SSL_CACERT_BADFILE',
		78 => 'CURLE_REMOTE_FILE_NOT_FOUND',
		79 => 'CURLE_SSH',
		80 => 'CURLE_SSL_SHUTDOWN_FAILED',
		81 => 'CURLE_AGAIN',
		82 => 'CURLE_SSL_CRL_BADFILE',
		83 => 'CURLE_SSL_ISSUER_ERROR',
		84 => 'CURLE_FTP_PRET_FAILED',
		84 => 'CURLE_FTP_PRET_FAILED',
		85 => 'CURLE_RTSP_CSEQ_ERROR',
		86 => 'CURLE_RTSP_SESSION_ERROR',
		87 => 'CURLE_FTP_BAD_FILE_LIST',
		88 => 'CURLE_CHUNK_FAILED');

	$curlErrno = 20;
if (in_array($curlErrno, $errCodes))
	{
		echo $errCodes[$curlErrno];
		
	}
2

Another pretty basic question. I have saved a result from curl in $html, but when I echo $html, it is in html that can be read by the browser. How can I echo it as just plain text, so <b> is just echoed as <b> and, doesn’t make something bold?

3

I think session in this context is meant more like execution session, if that makes any sense. Also curl supports a lot of protocols, which might and might not support sessions and cookies.
$ch stands for curl handle, which basically is a pointer to resource.
For checking your array, you should use array_key_exists instead, because 5 is a key not a value.
As dor second question, you might want to look in direction of php htmlspecialhars function to output readable html.

4

Thanks ronalds. It does make more sense and the rest of what you said also helps greatly. I messed up and had 5 in the post above, but meant to edit it to be 20, as specified in the code. (I was trying different numbers to see if it was just a special case.)

I am still a little unclear on what a resource is though, for example, compared to an object.

5

A resource is “a special variable, holding a reference to an external resource” (Source: PHP Manual). The types of Resource are explicitly defined (See the Appendix), and these resources may be referenced by the get_resource_type function. Certain functions will depend on receiving a Resource of a specific Type (mysql_query will expect a “mysql link” type resource, for example). If you dont define a link resource, PHP can automatically find the last-opened ‘mysql link’ resource, and use that. It couldnt do that if it were just looking for any Object.