Libcurl编译指南——Android和Windows系统

libcurl是一个免费且易于使用的客户端URL传输库，支持DICT、FILE、FTP、FTPS、Gopher、HTTP、HTTPS、IMAP、IMAPS、LDAP、LDAPS、POP3、POP3S、RTMP、RTSP、SCP、SFTP、SMTP、SMTPS、Telnet和TFTP。libcurl支持SSL证书，HTTP POST，HTTP PUT，FTP上传，基于HTTP表单的上传，代理，Cookie，用户+密码验证(Basic，Digest，NTLM，Negotiate，Kerberos)，文件传输恢复，http代理隧道等等！

libcurl是高度可移植的，它在许多平台上构建和工作相同，包括Solaris，NetBSD，FreeBSD，OpenBSD，Darwin，HPUX，IRIX，AIX，Tru64，Linux，UnixWare，Hurd，Windows，Amiga，OS/2，BeOS，Mac OS X，Ultrix，QNX，OpenVMS，RISC OS，Novell NetWare，DOS等等。

在当前进行的一个项目中，需要实现HTTP/HTTPS数据传输通信，且需要跨平台的代码编译运行。libcur为实现项目功能、代码复用和跨平台运行提供了稳定简单的解决方案。

平台

系统：Windows10 x64、Ubuntu16 x64
工具：Visual Studio 2017、Linux Android NDK

openssl：openssl-1.1.1b
zlib：zlib-1.2.11
libcurl：curl-7.65.3

Linux系统Android NDK编译libcurl

编译openssl

在openssl源码目录提供了在各个平台下编译的说明文本：

NOTES.ANDROID介绍了编译Android系统中openssl库的方法。
1、编译armeabi-v7a版本
环境变量设置：

生成Makefile：

# ./Configure android-arm threads shared --prefix=/home/workspace/android-plarfrom

编译：

# make
# make install

编译完成后在安装路径下可以找到目标文件：

2、编译arm64-v8a版本
环境变量设置：

生成Makefile：

# ./Configure android-arm64 threads shared --prefix=/home/workspace/android-plarfrom/openssl_64/target

编译：

# make
# make install 

编译完成后在安装路径下可以找到目标文件：

编译zlib

创建jni目录，拷贝zlib源码到jni目录下，并在目录下创建Android.mk：

LOCAL_PATH:= $(call my-dir)

#########################
# Build the libzip library

include $(CLEAR_VARS)

LOCAL_EXPORT_C_INCLUDES := $(LOCAL_PATH)

LOCAL_MODULE:= zlib
LOCAL_SRC_FILES:= adler32.c compress.c crc32.c \
 	deflate.c gzclose.c gzlib.c gzread.c gzwrite.c \
    infback.c inffast.c inflate.c inftrees.c \
    trees.c uncompr.c zutil.c

include $(BUILD_STATIC_LIBRARY) 

执行ndk-build编译：

# ndk-build

生成目标文件：

编译libcurl

libcur默认只支持HTTP通信，若要编译支持HTTPS的版本，需要依赖openssl和zlib。

1、创建jni目录。
2、将libcurl源码拷贝到jni目录下。
3、准备curl_config.h，并将其拷贝到源码lib目录下。

curl_config.h生成有两种方式：
（1）执行命令：

# ./configure --host=arm-linux-androideabi --with-ssl=PATH

NOTE：PATH一般应配置为openssl的ssl目录。
（2）手动生成.

4、修改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，掉注释掉宏定义HAVE_MALLOC_H和HAVE_IOCTL。

curl_config.h

/* lib/curl_config.h.  Generated from curl_config.h.in by configure.  */
/* lib/curl_config.h.in.  Generated from configure.ac by autoheader.  */
 
/* when building libcurl itself */
/* #undef BUILDING_LIBCURL */
 
/* Location of default ca bundle */
/* #undef CURL_CA_BUNDLE */
 
/* Location of default ca path */
/* #undef CURL_CA_PATH */
 
/* to disable cookies support */
/* #undef CURL_DISABLE_COOKIES */
 
/* to disable cryptographic authentication */
/* #undef CURL_DISABLE_CRYPTO_AUTH */
 
/* to disable DICT */
/* #undef CURL_DISABLE_DICT */
 
/* to disable FILE */
/* #undef CURL_DISABLE_FILE */
 
/* to disable FTP */
#define CURL_DISABLE_FTP 1
 
/* to disable HTTP */
/* #undef CURL_DISABLE_HTTP */
 
/* to disable IMAP */
#define CURL_DISABLE_IMAP 1
 
/* to disable LDAP */
#define CURL_DISABLE_LDAP 1
 
/* to disable LDAPS */
#define CURL_DISABLE_LDAPS 1
 
/* to disable POP3 */
#define CURL_DISABLE_POP3 1
 
/* to disable proxies */
/* #undef CURL_DISABLE_PROXY */
 
/* to disable RTSP */
#define CURL_DISABLE_RTSP 1
 
/* to disable SMTP */
#define CURL_DISABLE_SMTP 1
 
/* to disable TELNET */
#define CURL_DISABLE_TELNET 1
 
/* to disable TFTP */
#define CURL_DISABLE_TFTP 1
 
/* to disable verbose strings */
/* #undef CURL_DISABLE_VERBOSE_STRINGS */

/* to make a symbol visible */
/* #undef CURL_EXTERN_SYMBOL */
 
/* to enable hidden symbols */
/* #undef CURL_HIDDEN_SYMBOLS */
 
/* W$ LDAP with non-W$ compiler */
/* #undef CURL_LDAP_HYBRID */
 
/* Use W$ LDAP implementation */
/* #undef CURL_LDAP_WIN */
 
/* when not building a shared library */
/* #undef CURL_STATICLIB */
 
/* your Entropy Gathering Daemon socket pathname */
/* #undef EGD_SOCKET */
 
/* Define if you want to enable IPv6 support */
/* #undef ENABLE_IPV6 */
 
/* Define to the type qualifier of arg 1 for getnameinfo. */
#define GETNAMEINFO_QUAL_ARG1 const
 
/* Define to the type of arg 1 for getnameinfo. */
#define GETNAMEINFO_TYPE_ARG1 struct sockaddr *
 
/* Define to the type of arg 2 for getnameinfo. */
#define GETNAMEINFO_TYPE_ARG2 socklen_t
 
/* Define to the type of args 4 and 6 for getnameinfo. */
#define GETNAMEINFO_TYPE_ARG46 size_t
 
/* Define to the type of arg 7 for getnameinfo. */
#define GETNAMEINFO_TYPE_ARG7 int
 
/* Specifies the number of arguments to getservbyport_r */
/* #undef GETSERVBYPORT_R_ARGS */
 
/* Specifies the size of the buffer to pass to getservbyport_r */
/* #undef GETSERVBYPORT_R_BUFSIZE */
 
/* Define to 1 if you have the alarm function. */
#define HAVE_ALARM 1
 
/* Define to 1 if you have the <alloca.h> header file. */
#define HAVE_ALLOCA_H 1
 
/* Define to 1 if you have the <arpa/inet.h> header file. */
#define HAVE_ARPA_INET_H 1
 
/* Define to 1 if you have the <arpa/tftp.h> header file. */
/* #undef HAVE_ARPA_TFTP_H */
 
/* Define to 1 if you have the <assert.h> header file. */
#define HAVE_ASSERT_H 1
 
/* Define to 1 if you have the basename function. */
#define HAVE_BASENAME 1
 
/* Define to 1 if bool is an available type. */
#define HAVE_BOOL_T 1
 
/* Define to 1 if you have the clock_gettime function and monotonic timer. */
#define HAVE_CLOCK_GETTIME_MONOTONIC 1
 
/* Define to 1 if you have the closesocket function. */
/* #undef HAVE_CLOSESOCKET */
 
/* Define to 1 if you have the CloseSocket camel case function. */
/* #undef HAVE_CLOSESOCKET_CAMEL */
 
/* Define to 1 if you have the connect function. */
#define HAVE_CONNECT 1
 
/* Define to 1 if you have the `CRYPTO_cleanup_all_ex_data' function. */
/* #undef HAVE_CRYPTO_CLEANUP_ALL_EX_DATA */
 
/* Define to 1 if you have the <crypto.h> header file. */
/* #undef HAVE_CRYPTO_H */
 
/* Define to 1 if you have the <des.h> header file. */
/* #undef HAVE_DES_H */
 
/* Define to 1 if you have the <dlfcn.h> header file. */
#define HAVE_DLFCN_H 1
 
/* Define to 1 if you have the `ENGINE_cleanup' function. */
/* #undef HAVE_ENGINE_CLEANUP */
 
/* Define to 1 if you have the `ENGINE_load_builtin_engines' function. */
/* #undef HAVE_ENGINE_LOAD_BUILTIN_ENGINES */
 
/* Define to 1 if you have the <errno.h> header file. */
#define HAVE_ERRNO_H 1
 
/* Define to 1 if you have the <err.h> header file. */
/* #undef HAVE_ERR_H */
 
/* Define to 1 if you have the fcntl function. */
#define HAVE_FCNTL 1
 
/* Define to 1 if you have the <fcntl.h> header file. */
#define HAVE_FCNTL_H 1
 
/* Define to 1 if you have a working fcntl O_NONBLOCK function. */
#define HAVE_FCNTL_O_NONBLOCK 1
 
/* Define to 1 if you have the fdopen function. */
#define HAVE_FDOPEN 1
 
/* Define to 1 if you have the `fork' function. */
#define HAVE_FORK 1
 
/* Define to 1 if you have the freeaddrinfo function. */
#defi