jni中使用libcurl做网络开发

curl对android提供了支持，在curl的代码根目录中有相应的makefile文件Android.mk。使用libcrul必须先对curl进行交叉编译

一、curl的交叉编译：

1、编译android源代码。编译方法参考http://source.android.com。

2、在android源码中编译curl，从http://curl.haxx.se/download.html下载curl源码，解压到external/curl目录。

3、在external/curl目录中进行configure,（红色字部分根据自己的环境做相应的更改）

ANDROID_ROOT=`realpath /android/source/` && \

TOOLCHAIN_VER="4.4.0" \

PLATFORM_VER="8" \

CROSS_COMPILE=arm-eabi- \

PATH=$ANDROID_ROOT/prebuilt/linux-x86/toolchain/arm-eabi-$TOOLCHAIN_VER/bin:$PATH && \

CPPFLAGS="-I $ANDROID_ROOT/system/core/include -I$ANDROID_ROOT/bionic/libc/include -I$ANDROID_ROOT/ndk/build/platforms/android-5/arch-arm/usr/include -I$ANDROID_ROOT/bionic/libc/kernel/arch-arm -L $ANDROID_ROOT/prebuilt/linux-x86/toolchain/arm-eabi-$TOOLCHAIN_VER/lib/gcc/arm-eabi/$TOOLCHAIN_VER/interwork -L$ANDROID_ROOT/ndk/build/platforms/android-$PLATFORM_VER/arch-arm/usr/lib -L$ANDROID_ROOT/out/target/product/generic/system/lib " \

CFLAGS="-fno-exceptions -Wno-multichar -mthumb -mthumb-interwork -nostdlib -lc -ldl -lm " \

./configure CC=arm-eabi-gcc --host=arm-linux --disable-tftp --disable-sspi --disable-ipv6 --disable-ldaps --disable-ldap --disable-telnet --disable-pop3 --disable-ftp --without-ssl --disable-imap --disable-smtp --disable-pop3 --disable-rtsp --disable-ares --without-ca-bundle --disable-warnings --disable-manual --without-nss --enable-shared --without-zlib --without-random

如果需要openssl或zlib，可以把configure参数改为

./configure CC=arm-eabi-gcc --host=arm-linux --disable-tftp --disable-sspi --disable-ipv6 --disable-ldaps --disable-ldap --disable-telnet --disable-pop3 --disable-ftp --with-ssl=$ANDROID_ROOT/external/openssl --disable-imap --disable-smtp --disable-pop3 --disable-rtsp --disable-ares --without-ca-bundle --disable-warnings --disable-manual --without-nss --enable-shared --with-zlib=$ANDROID_ROOT/external/zlib --without-random

4、进入ANDROID_ROOT目录，执行source build/envsetup.sh,如果需要编译curl 执行make curl，或者仅编译libcurl make libcurl

5、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)

二、在jni中使用libcurl

1、在android源码目录中创建一个带jni的应用。

2、把libcurl的头文件拷贝到jni目录,在jni目录下创建3rd/include目录：

cp -r $ANDROID_ROOT/out/target/product/generic/obj/include/libcurl/curl/ jni/3rd/include

3、修改jni目录下的Android.mk文件，实例如下

LOCAL_PATH:= $(call my-dir)

include $(CLEAR_VARS)

LOCAL_C_INCLUDES += \

$(JNI_H_INCLUDE) \

$(LOCAL_PATH) \

$(LOCAL_PATH)/3rd/include \

LOCAL_PRELINK_MODULE:=false

LOCAL_STATIC_LIBRARIES := libcurl

LOCAL_MODULE:= libXXXXXX

LOCAL_MODULE_TAGS := optional

include $(BUILD_SHARED_LIBRARY)

4、事例代码如下：

#include "curl/curl.h"

#include <stdlib.h>

typedef struct pageInfo_t {

char *data;

int len;

} pageInfo_t;

static size_t

HTTPData(void *buffer, size_t size, size_t nmemb, void *userData) {

int len = size * nmemb;

pageInfo_t *page = (pageInfo_t *)userData;

if (buffer && page->data && (page->len + len < (16 * 1024)) ) { memcpy(&page->data[page->len], buffer, len);

page->len += len;

}

return len;

}

void curltest()

{

pageInfo_t page;

CURL *curl;

CURLcode res;

char *buffer;

page.data = (char *)malloc(16 * 1024);

page.len = 0;

if (page.data)

memset(page.data, 32, 16 * 1024);

buffer = (char *)malloc(1024);

curl = curl_easy_init();

if(curl) {

curl_easy_setopt(curl, CURLOPT_URL, "http://baihexss.sinaapp.com/plugin.html");

curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, HTTPData);

curl_easy_setopt(curl, CURLOPT_WRITEDATA, &page);

res = curl_easy_perform(curl);

/* always cleanup */

curl_easy_cleanup(curl);

if(res == 0) {

if (buffer) {

page.data[page.len < 256 ? page.len : 256] = '\0';

LOG("pagedata(%d): %s. done.\n", page.len, page.data);

}

}

LOG("Result %d", res);

} else {

LOG("Unable to init cURL");

}

}

5、在应用代码根目录执行mm编译，最后输出

============================================

PLATFORM_VERSION_CODENAME=REL

PLATFORM_VERSION=2.2.2

TARGET_PRODUCT=generic

TARGET_BUILD_VARIANT=eng

TARGET_SIMULATOR=

TARGET_BUILD_TYPE=release

TARGET_BUILD_APPS=

TARGET_ARCH=arm

HOST_ARCH=x86

HOST_OS=linux

HOST_BUILD_TYPE=release

BUILD_ID=FRG83G

============================================

make: Entering directory `/android/source'

target Non-prelinked: lib***** (out/target/product/generic/symbols/system/lib/lib*****.so)

Copying: out/target/common/obj/APPS/*****_intermediates/classes-full-debug.jar

Install: out/target/product/generic/data/app/*****.apk

Copy: out/target/product/generic/system/etc/apns-conf.xml

make: Leaving directory `/android/source'

6、把out/target/product/generic/data/app/*****.apk安装执行即可看到结果

备注：

开发环境：Android ndk1.5_r1,cygwinm

libcurl 7.19.6 源码 下载地址http://curl.haxx.se/

参考文章：http://blog.csdn.net/choujs/archive/2010/02/10/5304978.aspx

http://curl.haxx.se/mail/lib-2009-12/0071.html

如ndk开发一样，先刚libcurl源码放置 Android-ndk/source/sampel/ 下

在Android-ndk/apps 建相应的文件夹和application.mk

对ndk不熟悉可以先参考 Android ndk开发

1.在cygwin下，进入Android-ndk/ 目录, 运行 ./configure

自动checking 。（自过程需要花一些时间请耐心等待）

完成，自动创建相应配置文件

手动修改 lib/curl_config.h和src/curl_config.h，打开宏定义HAVE_LIBSSL、 HAVE_OPENSSL_CRYPTO_H、HAVE_OPENSSL_ERR_H、HAVE_OPENSSL_PEM_H、 HAVE_OPENSSL_PKCS12_H、HAVE_OPENSSL_RSA_H、HAVE_OPENSSL_SSL_H、 HAVE_OPENSSL_X509_H、USE_OPENSSL、USE_SSLEAY（但是注意android没有编译openssl中的 engine，因此不要打开宏定义HAVE_OPENSSL_ENGINE_H），同时注释掉宏定义HAVE_MALLOC_H和HAVE_IOCTL

（本段参考以上给出链接）

android.mk

LOCAL_PATH:=$(callmy-dir)

common_CFLAGS:=-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-DHAVE_CONFIG_H

#########################
#Buildthelibcurllibrary

include$(CLEAR_VARS)
include$(LOCAL_PATH)/lib/Makefile.inc

CURL_HEADERS:=/
curlbuild.h/
curl.h/
curlrules.h/
curlver.h/
easy.h/
mprintf.h/
multi.h/
stdcheaders.h/
typecheck-gcc.h/
types.h


LOCAL_SRC_FILES:=$(addprefixlib/,$(CSOURCES))
LOCAL_C_INCLUDES+=$(LOCAL_PATH)/include
LOCAL_CFLAGS+=/
$(common_CFLAGS)/
-I$(LOCAL_PATH)/include/
-I/usr/include

LOCAL_COPY_HEADERS_TO:=libcurl/curl
LOCAL_COPY_HEADERS:=$(addprefixinclude/curl/,$(CURL_HEADERS))

LOCAL_MODULE:=libcurl

include$(BUILD_STATIC_LIBRARY)

在cygwin中运行

make APP=libcurl -B

出现2个警告信息：

/ssluse.c: In function 'Curl_ossl_init':
/ssluse.c:632: warning: nested extern declaration of 'ENGINE_load_builtin_engines'

/strerror.c: In function 'Curl_strerror':
/strerror.c:642: warning: initialization makes pointer from integer without a cast

其他均无报错。但成功生成了libcurl.a文件。

测试过程：

测试中，发现IDN 的lib包始终找不到。

找了android的模拟器的lib文件下，也没有找到libidn 。所以准备重新编译libcurl.a，去掉与IDN相关的部分。

再次编译成功。

但在模拟器上始终得到7（Failed to connect() to host or proxy）

郁闷了一阵，最后发现应该在AndroidManifest.xml中

加入

<uses-permission android:name="android.permission.INTERNET"/>

再次测试，成功得到0。

编译完成！