curl_easy_setopt.html

专门介绍网络爬虫设计的论文,写得非常好啊.希望大家好好学习

<p class="level1">libcurl does not verify that the file has the correct properties set (as the standard Unix ftp client does). It should only be readable by user. 
<p class="level0"><a name="CURLOPTNETRCFILE"></a><span class="nroffip">CURLOPT_NETRC_FILE</span> 
<p class="level1">Pass a char * as parameter, pointing to a zero terminated string containing the full path name to the file you want libcurl to use as .netrc file. If this option is omitted, and <a class="emphasis" href="#CURLOPTNETRC">CURLOPT_NETRC</a> is set, libcurl will attempt to find the a .netrc file in the current user's home directory. (Added in 7.10.9) 
<p class="level0"><a name="CURLOPTUSERPWD"></a><span class="nroffip">CURLOPT_USERPWD</span> 
<p class="level1">Pass a char * as parameter, which should be [user name]:[password] to use for the connection. Use <a class="emphasis" href="#CURLOPTHTTPAUTH">CURLOPT_HTTPAUTH</a> to decide authentication method. 
<p class="level1">When using NTLM, you can set domain by prepending it to the user name and separating the domain and name with a forward (/) or backward slash (). Like this: "domain/user:password" or "domainuser:password". Some HTTP servers (on Windows) support this style even for Basic authentication. 
<p class="level1">When using HTTP and <a class="emphasis" href="#CURLOPTFOLLOWLOCATION">CURLOPT_FOLLOWLOCATION</a>, libcurl might perform several requests to possibly different hosts. libcurl will only send this user and password information to hosts using the initial host name (unless <a class="emphasis" href="#CURLOPTUNRESTRICTEDAUTH">CURLOPT_UNRESTRICTED_AUTH</a> is set), so if libcurl follows locations to other hosts it will not send the user and password to those. This is enforced to prevent accidental information leakage. 
<p class="level0"><a name="CURLOPTPROXYUSERPWD"></a><span class="nroffip">CURLOPT_PROXYUSERPWD</span> 
<p class="level1">Pass a char * as parameter, which should be [user name]:[password] to use for the connection to the HTTP proxy.  Use <a class="emphasis" href="#CURLOPTPROXYAUTH">CURLOPT_PROXYAUTH</a> to decide authentication method. 
<p class="level0"><a name="CURLOPTHTTPAUTH"></a><span class="nroffip">CURLOPT_HTTPAUTH</span> 
<p class="level1">Pass a long as parameter, which is set to a bitmask, to tell libcurl what authentication method(s) you want it to use. The available bits are listed below. If more than one bit is set, libcurl will first query the site to see what authentication methods it supports and then pick the best one you allow it to use. For some methods, this will induce an extra network round-trip. Set the actual name and password with the <a class="emphasis" href="#CURLOPTUSERPWD">CURLOPT_USERPWD</a> option. (Added in 7.10.6) 
<p class="level2">
<p class="level1"><a name="CURLAUTHBASIC"></a><span class="nroffip">CURLAUTH_BASIC</span> 
<p class="level2">HTTP Basic authentication. This is the default choice, and the only method that is in wide-spread use and supported virtually everywhere. This is sending the user name and password over the network in plain text, easily captured by others. 
<p class="level1"><a name="CURLAUTHDIGEST"></a><span class="nroffip">CURLAUTH_DIGEST</span> 
<p class="level2">HTTP Digest authentication.  Digest authentication is defined in RFC2617 and is a more secure way to do authentication over public networks than the regular old-fashioned Basic method. 
<p class="level1"><a name="CURLAUTHGSSNEGOTIATE"></a><span class="nroffip">CURLAUTH_GSSNEGOTIATE</span> 
<p class="level2">HTTP GSS-Negotiate authentication. The GSS-Negotiate (also known as plain "Negotiate") method was designed by Microsoft and is used in their web applications. It is primarily meant as a support for Kerberos5 authentication but may be also used along with another authentication methods. For more information see IETF draft draft-brezak-spnego-http-04.txt. 
<p class="level2">You need to build libcurl with a suitable GSS-API library for this to work. 
<p class="level1"><a name="CURLAUTHNTLM"></a><span class="nroffip">CURLAUTH_NTLM</span> 
<p class="level2">HTTP NTLM authentication. A proprietary protocol invented and used by Microsoft. It uses a challenge-response and hash concept similar to Digest, to prevent the password from being eavesdropped. 
<p class="level2">You need to build libcurl with OpenSSL support for this option to work, or build libcurl on Windows. 
<p class="level1"><a name="CURLAUTHANY"></a><span class="nroffip">CURLAUTH_ANY</span> 
<p class="level2">This is a convenience macro that sets all bits and thus makes libcurl pick any it finds suitable. libcurl will automatically select the one it finds most secure. 
<p class="level1"><a name="CURLAUTHANYSAFE"></a><span class="nroffip">CURLAUTH_ANYSAFE</span> 
<p class="level2">This is a convenience macro that sets all bits except Basic and thus makes libcurl pick any it finds suitable. libcurl will automatically select the one it finds most secure. 
<p class="level1">
<p class="level0"><a name="CURLOPTPROXYAUTH"></a><span class="nroffip">CURLOPT_PROXYAUTH</span> 
<p class="level1">Pass a long as parameter, which is set to a bitmask, to tell libcurl what authentication method(s) you want it to use for your proxy authentication.  If more than one bit is set, libcurl will first query the site to see what authentication methods it supports and then pick the best one you allow it to use. For some methods, this will induce an extra network round-trip. Set the actual name and password with the <a class="emphasis" href="#CURLOPTPROXYUSERPWD">CURLOPT_PROXYUSERPWD</a> option. The bitmask can be constructed by or'ing together the bits listed above for the <a class="emphasis" href="#CURLOPTHTTPAUTH">CURLOPT_HTTPAUTH</a> option. As of this writing, only Basic, Digest and NTLM work. (Added in 7.10.7) <a name="HTTP"></a><h2 class="nroffsh">HTTP OPTIONS</h2>
<p class="level0">
<p class="level0"><a name="CURLOPTAUTOREFERER"></a><span class="nroffip">CURLOPT_AUTOREFERER</span> 
<p class="level1">Pass a non-zero parameter to enable this. When enabled, libcurl will automatically set the Referer: field in requests where it follows a Location: redirect. 
<p class="level0"><a name="CURLOPTENCODING"></a><span class="nroffip">CURLOPT_ENCODING</span> 
<p class="level1">Sets the contents of the Accept-Encoding: header sent in an HTTP request, and enables decoding of a response when a Content-Encoding: header is received.  Three encodings are supported: <span Class="emphasis">identity</span>, which does nothing, <span Class="emphasis">deflate</span> which requests the server to compress its response using the zlib algorithm, and <span Class="emphasis">gzip</span> which requests the gzip algorithm.  If a zero-length string is set, then an Accept-Encoding: header containing all supported encodings is sent. 
<p class="level1">This is a request, not an order; the server may or may not do it.  This option must be set (to any non-NULL value) or else any unsolicited encoding done by the server is ignored. See the special file lib/README.encoding for details. 
<p class="level0"><a name="CURLOPTFOLLOWLOCATION"></a><span class="nroffip">CURLOPT_FOLLOWLOCATION</span> 
<p class="level1">A non-zero parameter tells the library to follow any Location: header that the server sends as part of an HTTP header. 
<p class="level1">This means that the library will re-send the same request on the new location and follow new Location: headers all the way until no more such headers are returned. <a class="emphasis" href="#CURLOPTMAXREDIRS">CURLOPT_MAXREDIRS</a> can be used to limit the number of redirects libcurl will follow. 
<p class="level0"><a name="CURLOPTUNRESTRICTEDAUTH"></a><span class="nroffip">CURLOPT_UNRESTRICTED_AUTH</span> 
<p class="level1">A non-zero parameter tells the library it can continue to send authentication (user+password) when following locations, even when hostname changed. This option is meaningful only when setting <a class="emphasis" href="#CURLOPTFOLLOWLOCATION">CURLOPT_FOLLOWLOCATION</a>. 
<p class="level0"><a name="CURLOPTMAXREDIRS"></a><span class="nroffip">CURLOPT_MAXREDIRS</span> 
<p class="level1">Pass a long. The set number will be the redirection limit. If that many redirections have been followed, the next redirect will cause an error (<span Class="emphasis">CURLE_TOO_MANY_REDIRECTS</span>). This option only makes sense if the <a class="emphasis" href="#CURLOPTFOLLOWLOCATION">CURLOPT_FOLLOWLOCATION</a> is used at the same time. Added in 7.15.1: Setting the limit to 0 will make libcurl refuse any redirect. Set it to -1 for an infinite number of redirects (which is the default) 
<p class="level0"><a name="CURLOPTPUT"></a><span class="nroffip">CURLOPT_PUT</span> 
<p class="level1">A non-zero parameter tells the library to use HTTP PUT to transfer data. The data should be set with <a class="emphasis" href="#CURLOPTREADDATA">CURLOPT_READDATA</a> and <a class="emphasis" href="#CURLOPTINFILESIZE">CURLOPT_INFILESIZE</a>. 
<p class="level1">This option is deprecated and starting with version 7.12.1 you should instead use <a class="emphasis" href="#CURLOPTUPLOAD">CURLOPT_UPLOAD</a>. 
<p class="level0"><a name="CURLOPTPOST"></a><span class="nroffip">CURLOPT_POST</span> 
<p class="level1">A non-zero parameter tells the library to do a regular HTTP post. This will also make the library use the a "Content-Type: application/x-www-form-urlencoded" header. (This is by far the most commonly used POST method). 
<p class="level1">Use the <a class="emphasis" href="#CURLOPTPOSTFIELDS">CURLOPT_POSTFIELDS</a> option to specify what data to post and <a class="emphasis" href="#CURLOPTPOSTFIELDSIZE">CURLOPT_POSTFIELDSIZE</a> to set the data size. 
<p class="level1">Optionally, you can provide data to POST using the <a class="emphasis" href="#CURLOPTREADFUNCTION">CURLOPT_READFUNCTION</a> and <a class="emphasis" href="#CURLOPTREADDATA">CURLOPT_READDATA</a> options but then you must make sure to not set <a class="emphasis" href="#CURLOPTPOSTFIELDS">CURLOPT_POSTFIELDS</a> to anything but NULL. When providing data with a callback, you must transmit it using chunked transfer-encoding or you must set the size of the data with the <a class="emphasis" href="#CURLOPTPOSTFIELDSIZE">CURLOPT_POSTFIELDSIZE</a> option. 
<p class="level1">You can override the default POST Content-Type: header by setting your own with <a class="emphasis" href="#CURLOPTHTTPHEADER">CURLOPT_HTTPHEADER</a>. 
<p class="level1">Using POST with HTTP 1.1 implies the use of a "Expect: 100-continue" header. You can disable this header with <a class="emphasis" href="#CURLOPTHTTPHEADER">CURLOPT_HTTPHEADER</a> as usual. 
<p class="level1">If you use POST to a HTTP 1.1 server, you can send data without knowing the size before starting the POST if you use chunked encoding. You enable this by adding a header like "Transfer-Encoding: chunked" with <a class="emphasis" href="#CURLOPTHTTPHEADER">CURLOPT_HTTPHEADER</a>. With HTTP 1.0 or without chunked transfer, you must specify the size in the request. 
<p class="level1">When setting <a class="emphasis" href="#CURLOPTPOST">CURLOPT_POST</a> to a non-zero value, it will automatically set <a class="emphasis" href="#CURLOPTNOBODY">CURLOPT_NOBODY</a> to 0 (since 7.14.1). 
<p class="level1">If you issue a POST request and then want to make a HEAD or GET using the same re-used handle, you must explicitly set the new request type using <a class="emphasis" href="#CURLOPTNOBODY">CURLOPT_NOBODY</a> or <a class="emphasis" href="#CURLOPTHTTPGET">CURLOPT_HTTPGET</a> or similar. 
<p class="level0"><a name="CURLOPTPOSTFIELDS"></a><span class="nroffip">CURLOPT_POSTFIELDS</span> 
<p class="level1">Pass a char * as parameter, which should be the full data to post in an HTTP POST operation. You must make sure that the data is formatted the way you want the server to receive it. libcurl will not convert or encode it for you. Most web servers will assume this data to be url-encoded. Take note. 
<p class="level1">This POST is a normal application/x-www-form-urlencoded kind (and libcurl will set that Content-Type by default when this option is used), which is the most commonly used one by HTML forms. See also the <a class="emphasis" href="#CURLOPTPOST">CURLOPT_POST</a>. Using <a class="emphasis" href="#CURLOPTPOSTFIELDS">CURLOPT_POSTFIELDS</a> implies <a class="emphasis" href="#CURLOPTPOST">CURLOPT_POST</a>. 
<p class="level1">Using POST with HTTP 1.1 implies the use of a "Expect: 100-continue" header. You can disable this header with <a class="emphasis" href="#CURLOPTHTTPHEADER">CURLOPT_HTTPHEADER</a> as usual. 
<p class="level1">To make multipart/formdata posts (aka rfc1867-posts), check out the <a class="emphasis" href="#CURLOPTHTTPPOST">CURLOPT_HTTPPOST</a> option. 
<p class="level0"><a name="CURLOPTPOSTFIELDSIZE"></a><span class="nroffip">CURLOPT_POSTFIELDSIZE</span> 
<p class="level1">If you want to post data to the server without letting libcurl do a strlen() to measure the data size, this option must be used. When this option is used you can post fully binary data, which otherwise is likely to fail. If this size is set to -1, the library will use strlen() to get the size. 
<p class="level0"><a name="CURLOPTPOSTFIELDSIZELARGE"></a><span class="nroffip">CURLOPT_POSTFIELDSIZE_LARGE</span> 
<p class="level1">Pass a curl_off_t as parameter. Use this to set the size of the <a class="emphasis" href="#CURLOPTPOSTFIELDS">CURLOPT_POSTFIELDS</a> data to prevent libcurl from doing strlen() on the data to figure out the size. This is the large file version of the <a class="emphasis" href="#CURLOPTPOSTFIELDSIZE">CURLOPT_POSTFIELDSIZE</a> option. (Added in 7.11.1) 
<p class="level0"><a name="CURLOPTHTTPPOST"></a><span class="nroffip">CURLOPT_HTTPPOST</span> 
<p class="level1">Tells libcurl you want a multipart/formdata HTTP POST to be made and you instruct what data to pass on to the server.  Pass a pointer to a linked list of curl_httppost structs as parameter. . The easiest way to create such a list, is to use <a class="emphasis" href="./curl_formadd.html">curl_formadd(3)</a> as documented. The data in this list must remain intact until you close this curl handle again with <a class="emphasis" href="./curl_easy_cleanup.html">curl_easy_cleanup(3)</a>. 
<p class="level1">Using POST with HTTP 1.1 implies the use of a "Expect: 100-continue" header. You can disable this header with <a class="emphasis" href="#CURLOPTHTTPHEADER">CURLOPT_HTTPHEADER</a> as usual. 
<p class="level1">When setting <a class="emphasis" href="#CURLOPTHTTPPOST">CURLOPT_HTTPPOST</a>, it will automatically set <a class="emphasis" href="#CURLOPTNOBODY">CURLOPT_NOBODY</a> to 0 (since 7.14.1). 
<p class="level0"><a name="CURLOPTREFERER"></a><span class="nroffip">CURLOPT_REFERER</span> 
<p class="level1">Pass a pointer to a zero terminated string as parameter. It will be used to set the Referer: header in the http request sent to the remote server. This can be used to fool servers or scripts. You can also set any custom header with <a class="emphasis" href="#CURLOPTHTTPHEADER">CURLOPT_HTTPHEADER</a>. 
<p class="level0"><a name="CURLOPTUSERAGENT"></a><span class="nroffip">CURLOPT_USERAGENT</span>