The difference between using arrays and strings for PHP's CURLOPT_POSTFIELDS parameter

This article will introduce to you the difference between arrays and strings used by PHP's CURLOPT_POSTFIELDS parameter. Friends who need to know more may feel free to refer to it.

PHP’s CURL component is a very commonly used HTTP request simulator.

Usually when sending post data, I have become accustomed to writing like this:
curl_setopt( $ch, CURLOPT_POSTFIELDS,$post_data);
But when sending a request to a certain server, the server returns 500. Use the socket method to connect to send requests and return normal data.

Try to send to a webpage with only . You can see that when using an array to send POST data, the CONTENT_TYPE received is as follows:

The code is as follows

Copy code

代码如下	复制代码
[CONTENT_TYPE] => multipart/form-data; boundary=—————————-f924413ea122 而使用http_build_query($post_data)，收到的CONTENT_TYPE如下： [CONTENT_TYPE] => application/x-www-form-urlencoded

[CONTENT_TYPE] => multipart/form-data; boundary=——————————-f924413ea122 When using http_build_query($post_data), the CONTENT_TYPE received is as follows: [CONTENT_TYPE] => application/x-www-form-urlencoded

It can be seen that when CURLOPT_POSTFIELDS is set to an array, the HTTP header will send Content_type: application/x-www-form-urlencoded. This is the header sent by the browser when submitting the form on a normal web page

. And multipart/form-data we know that this is the form used to upload files. Including the boundary delimiter will add many bytes.

The manual mentions:

The full data to post in a HTTP “POST” operation. To post a file, prepend a filename with @ and use the full path. This can either be passed as a urlencoded string like 'para1=val1¶2=val2&…' or as an array with the field name as key and field data as value. If value is an array, the Content-Type header will be set to multipart/form-data.

When using an array to provide post data, the CURL component is probably to be compatible with the @filename writing method for uploading files. By default, the content_type is set to multipart/form-data. Although it has no impact on most web servers, there are still a small number of servers that are incompatible.

The conclusion drawn in this article is that when there is no need to upload files, try to perform http_build_query on the data submitted by post and then send it out, which can achieve better compatibility and smaller request data packets.

The values of the following options will be used as long integers (specified in the option parameter):

• CURLOPT_INFILESIZE: When you upload a file to a remote site, this option tells PHP the size of the file you are uploading.
• CURLOPT_VERBOSE : If you want CURL to report every unexpected event, set this option to a non-zero value.
• CURLOPT_HEADER : If you want to include a header in the output, set this option to a non-zero value.
• CURLOPT_NOPROGRESS: If you do not want PHP to display a progress bar for CURL transfers, set this option to a non-zero value. Note: PHP automatically sets this option to a non-zero value, you should only change this option for debugging purposes.
• CURLOPT_NOBODY : If you do not want to include the body part in the output, set this option to a non-zero value.
• CURLOPT_FAILONERROR: If you want PHP not to display when an error occurs (HTTP code return greater than or equal to 300), set this option to a non-zero value. The default behavior is to return a normal page and ignore the code.
• CURLOPT_UPLOAD: If you want PHP to prepare for uploading, set this option to a non-zero value.
• CURLOPT_POST: If you want PHP to do a regular HTTP POST, set this option to a non-zero value. This POST is of the ordinary application/x-www-from-urlencoded type, mostly used by HTML forms.
• CURLOPT_FTPLISTONLY: Set this option to a non-zero value and PHP will list the directory names of FTP.
• CURLOPT_FTPAPPEND : Set this option to a non-zero value and PHP will apply the remote file instead of overwriting it.
• CURLOPT_NETRC: Set this option to a non-zero value and PHP will look in your ~./netrc file for the username and password of the remote site you want to connect to.
• CURLOPT_FOLLOWLOCATION : Set this option to a non-zero header (like "Location: ") and the server will send it as part of the HTTP header (note that this is recursive, PHP will send a header like "Location: ") .
• CURLOPT_PUT: Set this option to a non-zero value to upload a file using HTTP. To upload this file the CURLOPT_INFILE and CURLOPT_INFILESIZE options must be set.
• CURLOPT_MUTE: Set this option to a non-zero value and PHP will be completely silent for the CURL function.
• CURLOPT_TIMEOUT: Set a long integer as the maximum number of seconds.
• CURLOPT_LOW_SPEED_LIMIT: Set a long integer to control how many bytes are transmitted.
• CURLOPT_LOW_SPEED_TIME: Set a long integer to control how many seconds to transmit the number of bytes specified by CURLOPT_LOW_SPEED_LIMIT.
• CURLOPT_RESUME_FROM: Pass a long parameter containing the byte offset address (the starting form you want to transfer to).
• CURLOPT_SSLVERSION: Pass a long parameter containing the SSL version. By default PHP will be determined by its own efforts, in more security you have to set it manually.
• CURLOPT_TIMECONDITION: Pass a long parameter to specify how to handle the CURLOPT_TIMEVALUE parameter. You can set this parameter to TIMECOND_IFMODSINCE or TIMECOND_ISUNMODSINCE. This is only for HTTP.
• CURLOPT_TIMEVALUE: Pass a number of seconds from 1970-1-1 to now. This time will be used as the specified value by the CURLOPT_TIMEVALUE option, or by the default TIMECOND_IFMODSINCE.

The values of the following options will be treated as strings:

• CURLOPT_URL: This is the URL address you want to retrieve using PHP. You can also set this option during initialization with the curl_init() function.
• CURLOPT_USERPWD: Pass a string in the form of [username]:[password] and use PHP to connect.
• CURLOPT_PROXYUSERPWD: Pass a string in the format [username]:[password] to connect to the HTTP proxy.
• CURLOPT_RANGE: Pass a range you want to specify. It should be in "X-Y" format, with X or Y being excluded. HTTP transfers also support several intervals, separated by commas (X-Y,N-M).
• CURLOPT_POSTFIELDS: Pass a string containing all the data as an HTTP "POST" operation.
• CURLOPT_REFERER: A string containing a "referer" header in the HTTP request.
• CURLOPT_USERAGENT: A string containing a "user-agent" header in the HTTP request.
• CURLOPT_FTPPORT: Pass an IP address containing the IP address used by the ftp "POST" command. This POST instruction tells the remote server to connect to the IP address we specified. This string can be an IP address, a host name, a network interface name (under UNIX), or '-' (use the system default IP address).
• CURLOPT_COOKIE: Pass a header connection containing an HTTP cookie.
• CURLOPT_SSLCERT: Pass a string containing the certificate in PEM format.
• CURLOPT_SSLCERTPASSWD: Pass a password containing the necessary password to use the CURLOPT_SSLCERT certificate.
• CURLOPT_COOKIEFILE: Pass a string containing the name of the file containing cookie data. This cookie file can be in Netscape format, or it can be a stack of HTTP-style headers stored in the file.
• CURLOPT_CUSTOMREQUEST: When making an HTTP request, pass a character to be used by GET or HEAD. Pass a string to be used instead of GET or HEAD when doing an HTTP request. This is useful for doing or another, more obscure, HTTP request. Note: Make sure your server supports Order not to do it yet. The following options require a file description (obtained using the fopen() function):
• CURLOPT_FILE: This file will be the output file you place and transmit. The default is STDOUT.
• CURLOPT_INFILE: This file is the input file you sent.
• CURLOPT_WRITEHEADER: This file contains the header part of your output.
• CURLOPT_STDERR: This file has errors written instead of stderr. An example of obtaining a page that requires login. The current method is to log in once every time. People who need it will make improvements.

The difference between using arrays and strings for PHP's CURLOPT_POSTFIELDS parameter_PHP tutorial