libhttpd的使用
LibHttpd是一个开源轻量级嵌入式Web server，LibHttpd实现了下述功能：
- 实现了HTTP的子集；
- 使用表格技术自动处理Html Form数据；
- 产生的内容既可以是静态的网页，也可以是调用C函数动态产生的(callback)；
- LibHttpd提供API，利用这些API，用户可以很方便地将自己的Web内容加入到程序当中。
libhttpd中带有英文的使用手册，也增加了使用实例源码，在编程中可以做一个很好的模板：
#include "config.h"
#include
#include
#include
#ifdef _WIN32
# include
#else
# include time.h>
#endif
#include "httpd.h"
/*
** This is a static page of HTML. It is loaded into the content
** tree using httpdAddStaticContent( ).
*/
#define test1_html "This is just a test"
#define ember_code1 "printf(\"This is from ember in process %d\n\",getpid());"
#define ember_code "load \"/usr/local/nk/www/content.lib\"; dispatchWebPage(\"/index.html\");"
/*
** Below are 2 dynamic pages, each generated by a C function. The first
** is a simple page that offers a little dynamic info (the process ID)
** and the setups up a test link and a simple form.
**
** The second page processes the form. As you can see, you can access
** the form data from within your C code by accessing the symbol table
** using httpdGetVariableByName() (and other similar functions). You
** can also include variables in the string passed to httpdOutput( ) and
** they will be expanded automatically.
*/
void index_html(server)
httpd *server;
{
httpdPrintf(server,
"Welcome to the httpd server running in process number %d\n"
,
getpid());
httpdPrintf(server,
"Click here to view a test page\n"
);
httpdPrintf(server,
"Click here to authenticate\n"
);
httpdPrintf(server,
"Or here for a test wildcard page\n"
);
httpdPrintf(server, ");
httpdPrintf(server, "Enter your name \n");
httpdPrintf(server, "\n"
);
return;
}
void test2_html(server)
httpd *server;
{
httpVar *variable;
/*
** Grab the symbol table entry to see if the variable exists
*/
variable = httpdGetVariableByName(server, "name");
if (variable == NULL)
{
httpdPrintf(server,"Missing form data!");
return;
}
/*
** Use httpdOutput() rather than httpdPrintf() so that the variable
** embedded in the text is expanded automatically
*/
httpdOutput(server,"Hello $name");
}
void test3_html(server)
httpd *server;
{
char *path;
path = httpdRequestPath(server);
httpdOutput(server,"Wilcard dynamic request received"
);
httpdPrintf(server,"The requested path was %s"
, path);
}
void login_html(server)
httpd *server;
{
if (httpdAuthenticate(server, "LibHTTPD Test") == 0)
return;
httpdPrintf(server, "Your username is '%s'\n"
,
server->request.authUser);
httpdPrintf(server, "Your password is '%s'\n"
,
server->request.authPassword);
httpdOutput(server,
"Click here to force reauthentication");
httpdOutput(server, ". Use a username = test password = 123");
}
void login2_html(server)
httpd *server;
{
if (httpdAuthenticate(server, "LibHTTPD Test") == 0)
{
httpdOutput(server, "Authentication failure(1).");
return;
}
if (strcmp(server->request.authUser, "test") != 0 ||
strcmp(server->request.authPassword, "123") != 0)
{
httpdForceAuthenticate(server, "LibHTTPD Test");
httpdOutput(server, "Authentication failure (2).");
return;
}
httpdOutput(server, "Your login was accepted.");
}
void myError404Handler(server, error)
httpd *server;
int error;
{
httpdOutput(server,"Whoa there. You hit a page that doesn't exist!
\n"
);
httpdOutput(server,"Or in other words : Error 404\n\n");
}
int main(argc, argv)
int argc;
char *argv[];
{
httpd *server;
char *host;
int port,
errFlag,
result;
extern char *optarg;
extern int optind, opterr, optopt;
int c;
struct timeval timeout;
host = NULL;
port = 80;
errFlag = 0;
while ( (c=getopt(argc,argv,"h:p:")) != -1 )
{
switch ( c )
{
case 'h':
host=optarg;
break;
case 'p':
port = atoi(optarg);
break;
default:
errFlag++;
}
}
if (errFlag)
{
fprintf(stderr,"usage: [-h ] [ -p ]\n" );
fprintf(stderr,"\nLibHTTPD version %s\n\n",LIBHTTPD_VERSION);
exit(1);
}
/*
** Ensure that PIPE signals are either handled or ignored.
** If a client connection breaks while the server is using
** it then the application will be sent a SIGPIPE. If you
** don't handle it then it'll terminate your application.
*/
signal(SIGPIPE, SIG_IGN);
/*
** Create a server and setup our logging
*/
server = httpdCreate(host,port);
if (server == NULL)
{
perror("Can't create server");
exit(1);
}
httpdSetAccessLog(server, stdout);
httpdSetErrorLog(server, stdout);
/*
** We are fussy and don't want the default Error 404 page
*/
httpdSetErrorFunction(server,404, myError404Handler);
/*
** Setup some content for the server
*/
httpdAddCContent(server,"/", "index.html", HTTP_TRUE,
NULL, index_html);
httpdAddCContent(server,"/", "test2.html", HTTP_FALSE,
NULL, test2_html);
httpdAddCContent(server,"/", "login.html", HTTP_FALSE,
NULL, login_html);
httpdAddCContent(server,"/", "login2.html", HTTP_FALSE,
NULL, login2_html);
httpdAddCWildcardContent(server,"/wildcard", NULL, test3_html);
httpdAddStaticContent(server, "/", "test1.html", HTTP_FALSE,
NULL, test1_html);
httpdAddEmberContect(server,"/","ember.html", HTTP_FALSE,
NULL, ember_code);
/*
** Go into our service loop
*/
while(1 == 1)
{
/*
** Linux modifies the timouet value during the
** select call so we must set it everyt ime. Most
** other UNIX implementations do not modify timeout
** but it doesn't hurt to set it each time anyway
*/
timeout.tv_sec = 5;
timeout.tv_usec = 0;
result = httpdGetConnection(server, &timeout);
if (result == 0)
{
printf("Timeout ... \n");
continue;
}
if (result < 0)
{
printf("Error ... \n");
continue;
}
if(httpdReadRequest(server) < 0)
{
httpdEndRequest(server);
continue;
}
httpdProcessRequest(server);
httpdEndRequest(server);
}
}
以下转载于网络博客中关于libhttpd接口函数的功用，更详细的函数功能参看libhttpd manual:
----------------------------------------------------------------------------------
httpdCreate ( ) 创建WEB服务器
httpd * httpdCreate ( host , port )
char * host
int port
Example :
server = httpdCreate( “192.168.1.1”, HTTP_PORT);
if ( server == NULL )
perror ( “Couldn’t create HTTP server” );
server2 = httpdCreate ( NULL , 2048 );
------------------------------------------------------------------------------------
httpdSetAccessLog( ) 设置访问日志文件
httpdSetAccessLog ( server, fp )
httpd *server;
FILE *fp;
Example :
fp = fopen ( “/tmp/access.log”, “a” );
httpdSetAccessLog ( server, fp );
--------------------------------------------------------------------
httpdSetErrorLog( ) 设置错误日志文件
httpdSetErrorLog ( server, fp )
httpd *server;
FILE *fp;
Example :
httpdSetErrorLog ( server, stderr );
------------------------------------------------------------------------
httpdSetFileBase( ) 设置文件基本路径名
httpdSetErrorLog ( server, path )
httpd *server;
char *path;
Example :
httpdSetFileBase ( server, “/usr/local/www-pages” );
------------------------------------------------------------------------
httpdAddCContent( ) 调用C函数产生输出内容
httpdAddCContent ( server, dir, name, indexFlag, preload, functPtr )
httpd *server;
char *dir, *name;
int indexFlag, (*)( )preload;
void (*)( ) functPtr;
Example :
void index_callbackl ( server )
httpd *server;
{
httpdOutput(server, “Hello There\n”);
}
httpdAddCContent( server, “/”, “index.html”, HTTP_TRUE, NULL, index_callback);
------------------------------------------------------------------------------------
httpdAddFileContent( ) 将一个外部文件加入到输出内容
httpdAddFileContent ( server, dir, name, indexFlag, preload, path )
httpd *server;
char *dir, *name;
int indexFlag, (*) ( ) preload;
char *path;
Example :
httpdAddFileContent( server, “/”, “index.html”, HTTP_TRUE, NULL, “/usr/local/www/index.html” );
-----------------------------------------------------------------------------------
httpdAddStaticContent( ) 将一个内部文本BUFFER加入到HTML输出内容
httpdAddStaticContent ( server, dir, name, indexFlag, preload, buf )
httpd *server;
char *dir, *name;
int indexFlag, (*)( ) preload;
char *buf;
Example :
#define index_content “Hello There\n”
httpdAddStaticContent( server, “/”, “index.html”, HTTP_TRUE, NULL, index_content );
------------------------------------------------------------------------------------
httpdAddWildcardContent( ) 增加与通配符匹配的文件内容
httpdAddWildcardContent ( server, dir, preload, path )
httpd *server;
char *dir;
int (*) ( )preload;
char *path;
Example :
httpdAddWildcardContent(server,“/graphics”, NULL, “/usr/local/www/graphics” );
-----------------------------------------------------------------------------------
httpdAddCWildcardContent( ) 请求指定目录中的任何文件时调用C回调函数
httpdAddCWildcardContent ( server, dir, preload, functPtr )
httpd *server;
char *dir;
int (*) ( )preload;
void (*)( ) functPtr;
Example :
httpdAddCWildcardContent(server,“/users”, NULL, send_user_info );
---------------------------------------------------------------------------------
httpdGetConnection ( ) 接受一个HTTP连接请求
int httpdGetConnection ( server , timeout)
httpd *server;
struct timeval *timeout;
-----------------------------------------------------------------------
httpdReadRequest ( ) 读取并保存从客户端发送过来的请求和数据
int httpdReadRequest ( server )
httpd *server;
-------------------------------------------------------------------------
httpdProcessRequest ( ) 对请求进行处理，并将请求内容发送到客户端浏览器
httpdProcessRequest ( server )
httpd *server;
----------------------------------------------------------------------
httpdEndRequest ( ) 请求结束处理
httpdEndRequest ( server )
httpd *server;
----------------------------------------------------------------------
httpdOutput ( ) 将文本BUFFER内容发送到客户端浏览器
httpdOutput ( server, buffer )
httpd *server;
char *buffer
Example :
httpdOutput ( server, “Hello $name. Welcome to the test server” );
----------------------------------------------------------------------
httpdPrintf ( ) 按指定格式将内容输出到客户端浏览器
httpdPrintf ( server, format, arg, arg, … )
httpd *server;
char *format;
Example :
httpdPrintf( server, “Hello %s. Welcome to the server running in process number %d”，
username, getpid( ) );
-------------------------------------------------------------------------
httpdSetContentType ( ) 设置除HTML文本以外的内容类型
httpdSetContentType( server, type )
httpd *server;
char *type
Example :
httpdSetContentType ( server, “image/jpeg” );
------------------------------------------------------------------------
httpdSetResponse ( ) 设置返回给客户端浏览器的的响应代码
httpdSetResponse( server, responseInfo )
httpd *server;
char *responseInfo;
Example :
httpdSetResponse ( server, “301 Moved Permanently” );
-------------------------------------------------------------------
httpdAddHeader ( ) 增加HTML头内容
httpdAddHeader( server, header )
httpd *server;
char *header;
Example :
httpdSetResponse ( server, “307 Temporary Redirect” );
httpdAddHeader ( server, “Location: http://www.foo.com/some/new/location”);
---------------------------------------------------------------------------------
httpdSendHeaders( ) 发送HTML头
httpdSendHeaders( server)
httpd *server;
Example :
httpdSetContentType ( server, “image/jpeg” );
httpdSendHeaders ( server );
generateJpegData( server );
---------------------------------------------------------------------------------
httpVar * httpdGetVariableByName ( ) 在符号表中查找变量
httpdGetVariableByName( server, varName )
httpd *server;
char *varName;
Example :
varPtr = httpdGetVariableByName ( server, “username” );
if ( varPtr != NULL)
uname = varPtr->value ;
------------------------------------------------------------------------------
httpVar * httpdGetVariableByPrefix ( ) 获取第一个与指定前缀相匹配的变量
httpdGetVariableByPrefixe( server, prefix )
httpd *server;
char *prefix;
-------------------------------------------------------------------------
httpVar * httpdGetNextVariableByPrefix ( ) 获取下一个与指定前缀相匹配的变量
httpdGetNextVariableByPrefixe( varPtr, prefix )
httpVar *varPtr;
char *prefix;
Example :
varPtr = httpdGetVariableByPrefix ( server, “hughes_” );
while ( varPtr != NULL )
{
printf(“Name = %s, Value = %s \n”, varPtr->name, varPtr->value;
varPtr = httpdGetNextVariableByPrefix ( varPtr, “hughes_” );
}
------------------------------------------------------------------------
httpVar * httpdGetVariableByPrefixedName ( ) 在符号表中查找变量
httpdGetVariableByPrefixedName( varPtr, prefix, remainder )
httpVar *varPtr;
char *prefix, *remainder;
Example :
prefixPtr = httpdGetVariableByName ( server, “multi-select-values” );
while ( prefixPtr != NULL )
{
prefix = prefixPtr->value;
varPtr = httpdGetVariableByPrefixedName(server, prefix, “_username”);
printf(“%s_username = %s\n”, prefix, varPtr->value;
prefixPtr = prefixPtr->nextValue;
}
------------------------------------------------------------------------------
httpdAddVariable( ) 在符号表中增加变量
httpdAddVariable( server, name, value )
httpd *server;
char *name, *value;
Example :
httpdAddVariable( server, “background_color”, “#FFFF30” );
httpdOutput( server, “\n”);
---------------------------------------------------------------------------
httpdDumpVariables( ) Dump符号表内容
httpdDumpVariables( server )
httpd *server;
-------------------------------------------------------------------------
httpdSet( ) 设置
httpdSet( server, name, value )
httpd *server;
char *name, *value;
---------------------------------------------------------------------------
httpdAuthenticate( ) 使用用户名和口令进行身份认证
httpdAuthenticate( server, realm )
httpd *server;
char *realm;
---------------------------------------------------------------------------
httpdForceAuthenticate( ) 强迫身份认证
httpdForceAuthenticate( server, realm )
httpd *server;
char *realm;
------------------------------------------------------------------------------
httpdAddAcl( ) 在ACL表中增加访问控制项
httpdAddAcl( server, acl, cidrAddr, action )
httpd *server;
httpAcl *acl;
char *cidrAddr;
int action
-----------------------------------------------------------------------------
httpdSetDefaultAcl( ) 设置默认ACL
httpdSetDefaultAcl( server, acl )
httpd *server;
httpAcl *acl;
--------------------------------------------------------------------
httpdCheckAcl( ) 进行ACL检查
httpdCheckAcl( server, acl )
httpd *server;
httpAcl *acl;
-------------------------------------------------------------------
httpdUrlEncode( ) 进行URL解码
char * httpdUrlEncode( buf )
char *buf;
-------------------------------------------------------------------
httpdRequestMethod( ) 获取访问方式（HTTP_GET/HTTP_POST）
int httpdRequestMethod( server )
httpd *server;
--------------------------------------------------------------------
httpdRequestMethodName( ) 获取访问方式名字
char *httpdRequestMethodName( server )
httpd *server;
------------------------------------------------------------------
httpdRequestPath( ) 获取URL请求路径
char *httpdRequestPath( server )
httpd *server;
----------------------------------------------------------------------
httpdRequestContentType( ) 获取当前请求内容类型
char *httpdRequestContentType( server )
httpd *server;
-----------------------------------------------------------------------
httpdRequestContentLength( ) 获取当前请求发送的内容长度
int httpdRequestContentLength( server )
httpd *server;
-----------------------------------------------------------------------