curl Expect:100-continue

curl Expect:100-continue

When using curl POST data, if the POST data is greater than 1024 bytes , curl will not directly initiate a POST request. Instead, it will be done in two steps.

1. Send a request with an Expect:100-continue in the header to ask the server if it is willing to accept data.

2. After receiving the 100-continue response from the server, POST the data to the server.

This is defined by libcurl. For details, you can view the relevant description: http://www.w3.org/Protocols/rfc2616/rfc2616-sec8.html#sec8.2.3

So this will appear one question. Not all servers will respond with 100-continue. For example, lighttpd will return "417 Expectation Fail", which will cause logical errors.

The solution is as follows: when sending a request, the header contains an empty Expect.

curl_setopt($ch, CURLOPT_HTTPHEADER, array("Expect:"));

The above has introduced curl Expect:100-continue, including the relevant content. I hope it will be helpful to friends who are interested in PHP tutorials.