libcurl主要功能就是用不同的协议连接和沟通不同的服务器~也就是相当封装了的sockPHP 支持libcurl(允许你用不同的协议连接和沟通不同的服务器)。, libcurl当前支持http, https, ftp, gopher, telnet, dict, file, 和ldap 协议。libcurl同样支持HTTPS证书授权,HTTP POST,
HTTP PUT, FTP 上传(当然你也可以使用PHP的ftp扩展), HTTP基本表单上传,代理,cookies,和用户认证。
Libcurl为一个免费开源的,客户端url传输库,支持FTP,FTPS,TFTP,HTTP,HTTPS,GOPHER,TELNET,DICT,FILE和LDAP,跨平台,支持Windows,Unix,Linux等,线程安全,支持Ipv6。并且易于使用。
从http://curl.haxx.se/libcurl/ 下载一个稳定的版本,注意选择OS。
在使用之前请大家多阅读libcurl的文档:因为如果要实际运用到项目中,最好对libcurl有具体的了解,具体在
http://curl.haxx.se/libcurl/c/
curl_easy_setopt()
curl_easy_perform()
curl_easy_getinfo()
这三个函数的使用上,需要多去钻研,多看Samples,你才能灵活使用libcurl。
感谢这篇文章:
http://blog.163.com/xu_chao2000/blog/static/27770610200801303252802/
给了我许多启发,再次感谢!
给出我的一个简单的代码例子:
说明:
1.关键在curl_easy_setopt函数设置option,可以设置ftp,http,get,post等许多选项,请根据具体使用情况设置。
2.对取回来的数据需要进行判断,比如http下载文件,如果文件不存在,需要进行处理。因为writer是可以将buf填充404 not found等网页内容的,不能将这个内容当成文件内容,所以需要判断http web返回来的code,进行判断。
3.我有个问题,就是想得到服务器上filename的具体名称,verbose调试已经返回了,但是我在getinfo的时候,试过好多选项,但未找到这个存放真实服务器文件名的选项,如果有知道的麻烦告诉我,谢谢了!
#include "curl/curl.h"
#pragma comment(lib, "libcurl.lib")
long writer(void *data,
int size, int nmemb, string &content);
bool CurlInit(CURL *&curl,
const char* url,string &content);
bool GetURLDataBycurl(const char* URL, string &content);
void main()
{
char *url ="http://www.baidu.com/img/baidu.gif";
string content;
if ( GetURLDataBycurl(url,content))
{
printf("%s\n",content);
}
getchar();
}
bool CurlInit(CURL *&curl,
const char* url,string &content)
{
CURLcode code;
string error;
curl = curl_easy_init();
if (curl == NULL)
{
printf( "Failed to create CURL connection\n");
return false;
}
code = curl_easy_setopt(curl, CURLOPT_ERRORBUFFER, error);
if (code != CURLE_OK)
{
printf( "Failed to set error buffer [%d]\n", code );
return false;
}
curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
code = curl_easy_setopt(curl, CURLOPT_URL, url);
if (code != CURLE_OK)
{
printf("Failed to set URL [%s]\n", error);
return false;
}
code = curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1);
if (code != CURLE_OK)
{
printf( "Failed to set redirect option [%s]\n", error );
return false;
}
code = curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, writer);
if (code != CURLE_OK)
{
printf( "Failed to set writer [%s]\n", error);
return false;
}
code = curl_easy_setopt(curl, CURLOPT_WRITEDATA, &content);
if (code != CURLE_OK)
{
printf( "Failed to set write data [%s]\n", error );
return false;
}
return true;
}
long writer(void *data,
int size, int nmemb, string &content)
{
long sizes = size * nmemb;
string temp(data,sizes);
content += temp;
return sizes;
}
bool GetURLDataBycurl(const char* URL, string &content)
{
CURL *curl = NULL;
CURLcode code;
string error;
code = curl_global_init(CURL_GLOBAL_DEFAULT);
if (code != CURLE_OK)
{
printf( "Failed to global init default [%d]\n", code );
return false;
}
if ( !CurlInit(curl,URL,content) )
{
printf( "Failed to global init default [%d]\n" );
return PM_FALSE;
}
code = curl_easy_perform(curl);
if (code != CURLE_OK)
{
printf( "Failed to get '%s' [%s]\n", URL, error);
return false;
}
long retcode = 0;
code = curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE , &retcode);
if ( (code == CURLE_OK) && retcode == 200 )
{
double length = 0;
code = curl_easy_getinfo(curl, CURLINFO_CONTENT_LENGTH_DOWNLOAD , &length);
printf("%d",retcode);
FILE * file = fopen("1.gif","wb");
fseek(file,0,SEEK_SET);
fwrite(content.c_str(),1,length,file);
fclose(file);
//struct curl_slist *list;
//code = curl_easy_getinfo(curl,CURLINFO_COOKIELIST,&list);
//curl_slist_free_all (list);
return true;
}
else
{
// debug1( "%s \n ",getStatusCode(retcode));
return false;
}
curl_easy_cleanup(curl);
return false;
}
由于项目需要在NDK中使用网络开发,对于c语言网络开发来说,libcurl库是个很不错的选择,但android系统中并没有自带该库,所以就得自己移植了。
下面是移植步骤:
1. 下载curl源码
我这里下载的是curl-7.22.0,源码下载地址为:http://curl.haxx.se/download.html
2. 准备android源码编译环境,
android源码应已全部编译过,具体细节这里不详述,我这里使用的是android2.2 froyo源码树。
3. 在android中编译curl
在最新的curl源码里其实已经带有Android.mk这个编译文件了,而且在这文件的开头注释部分比较详细地介绍编译方法。
1)拷贝curl源码至android源码树下的external/curl
2)cd 到 external/curl目录下,输入(红色字部分根据自己的环境做相应的更改):
ANDROID_HOME=/home/braincol/workspace/android/froyo && \
NDK_HOME=/home/braincol/workspace/android/froyo/ndk && \
PATH="$ANDROID_HOME/prebuilt/linux-x86/toolchain/arm-eabi-4.4.0/bin:$PATH" \
./configure --host=arm-linux CC=arm-eabi-gcc --with-random=/dev/urandom \
CPPFLAGS="-I$NDK_HOME/platforms/android-8/arch-arm/usr/include \
-I $ANDROID_HOME/external/curl/include/ \
-I $ANDROID_HOME/external/curl/3rd/include \
-I $ANDROID_HOME/external/curl \
-I $ANDROID_HOME/out/target/product/generic/obj/STATIC_LIBRARIES/libcurl_intermediates \
-I $ANDROID_HOME/dalvik/libnativehelper/include/nativehelper \
-I $ANDROID_HOME/system/core/include \
-I $ANDROID_HOME/hardware/libhardware/include \
-I $ANDROID_HOME/hardware/libhardware_legacy/include \
-I $ANDROID_HOME/hardware/ril/include \
-I $ANDROID_HOME/dalvik/libnativehelper/include \
-I $ANDROID_HOME/frameworks/base/include \
-I $ANDROID_HOME/frameworks/base/opengl/include \
-I $ANDROID_HOME/frameworks/base/native/include \
-I $ANDROID_HOME/external/skia/include \
-I $ANDROID_HOME/out/target/product/generic/obj/include \
-I $ANDROID_HOME/bionic/libc/arch-arm/include \
-I $ANDROID_HOME/bionic/libc/include \
-I $ANDROID_HOME/bionic/libstdc++/include \
-I $ANDROID_HOME/bionic/libc/kernel/common \
-I $ANDROID_HOME/bionic/libc/kernel/arch-arm \
-I $ANDROID_HOME/bionic/libm/include \
-I $ANDROID_HOME/bionic/libm/include/arch/arm \
-I $ANDROID_HOME/bionic/libthread_db/include \
-include $ANDROID_HOME/system/core/include/arch/linux-arm/AndroidConfig.h \
-I $ANDROID_HOME/system/core/include/arch/linux-arm/ \
-D__ARM_ARCH_5__ -D__ARM_ARCH_5T__ -D__ARM_ARCH_5E__ -D__ARM_ARCH_5TE__ -DANDROID -DNDEBUG -DNDEBUG -DHAVE_CONFIG_H" \
CFLAGS="-fno-exceptions -Wno-multichar -msoft-float -fpic -ffunction-sections \
-funwind-tables -fstack-protector -Wa,--noexecstack -Werror=format-security \
-fno-short-enums -march=armv5te -mtune=xscale -Wno-psabi -mthumb-interwork \
-fmessage-length=0 -W -Wall -Wno-unused -Winit-self -Wpointer-arith \
-Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point \
-g -Wstrict-aliasing=2 -finline-functions -fno-inline-functions-called-once \
-fgcse-after-reload -frerun-cse-after-loop -frename-registers -UDEBUG \
-mthumb -Os -fomit-frame-pointer -fno-strict-aliasing -finline-limit=64 \
-Wpointer-arith -Wwrite-strings -Wunused -Winline -Wnested-externs \
-Wmissing-declarations -Wmissing-prototypes -Wno-long-long -Wfloat-equal \
-Wno-multichar -Wsign-compare -Wno-format-nonliteral -Wendif-labels \
-Wstrict-prototypes -Wdeclaration-after-statement -Wno-system-headers" \
LIBS="-nostdlib -Bdynamic -Wl,-T,$ANDROID_HOME/build/core/armelf.x \
-Wl,-dynamic-linker,/system/bin/linker -Wl,--gc-sections -Wl,-z,nocopyreloc \
-L$ANDROID_HOME/out/target/product/generic/obj/lib -Wl,-z,noexecstack \
-Wl,-rpath-link=$ANDROID_HOME/out/target/product/generic/obj/lib \
-lc -llog -lcutils -lstdc++ \
-Wl,--no-undefined $ANDROID_HOME/prebuilt/linux-x86/toolchain/arm-eabi-4.4.0/lib/gcc/arm-eabi/4.4.0/libgcc.a \
$ANDROID_HOME/out/target/product/generic/obj/lib/crtend_android.o \
-lm $ANDROID_HOME/out/target/product/generic/obj/lib/crtbegin_dynamic.o \
-L$ANDROID_HOME/external/curl/3rd/libs"
如果$ANDROID_HOME目录下没有ndk的开发包,那么到google的官网上下载一个放进去就行了。
3)cd 到源码根目录 mmm extern/libcurl:
编译完成之后,会生成静态库:out/target/product/generic/obj/STATIC_LIBRARIES/libcurl_intermediates/libcurl.a 。
4)如果要生成动态库需要修改curl下的Android.mk :
LOCAL_PRELINK_MODULE := false
LOCAL_MODULE:= libcurl
LOCAL_MODULE_TAGS := optional
# Copy the licence to a place where Android will find it.
# Actually, this doesn't quite work because the build system searches
# for NOTICE files before it gets to this point, so it will only be seen
# on subsequent builds.
ALL_PREBUILT += $(LOCAL_PATH)/NOTICE
$(LOCAL_PATH)/NOTICE: $(LOCAL_PATH)/COPYING | $(ACP)
$(copy-file-to-target)
#include $(BUILD_STATIC_LIBRARY)
include $(BUILD_SHARED_LIBRARY)
4. 在android中测试curl
1)在android froyo源码树中下建立一个mytest目录,该目录下再建立一个curltest目录。
2)在目录curtest下创建curl-test.cpp:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
|
#include #include int main() CURL
|