一個簡單的HTTPS GET 程式

用CURL完成一個簡單的HTTPS GET 程式

CURL 一套  open source 命令列工具與函式庫, 以URL語法格式傳送資料

支援協定: DICT, FILE, FTP, FTPS, Gopher, HTTP, HTTPS, IMAP, IMAPS, LDAP, LDAPS, POP3, POP3S, RTMP, RTSP, SCP, SFTP, SMB, SMTP, SMTPS, Telnet and TFTP. curl supports SSL certificates, HTTP POST, HTTP PUT, FTP uploading, HTTP form based upload, proxies, HTTP/2, cookies, user+password authentication (Basic, Plain, Digest, CRAM-MD5, NTLM, Negotiate and Kerberos)等協定

安裝:  讓libcurl 支援 https 協定, 必須先安裝 OpenSSL 才會有https的支援

•  (1) 先安裝及下載OpenSSL 函式庫

下載 wget https://www.openssl.org/source/old/0.9.x/openssl-0.9.8y.tar.gz

再進行OpenSSL 函式庫編譯與安裝

tar zxvf openssl-0.9.8y.tar.gz

cd openssl-0.9.8y

make 

make install

•  安裝libcurl 函式庫

./configure --with-ssl

make 

make install

執行完configure 後, 顯示,目前支擾的協定狀態

目前curl 工具支援的協定

root@raspberrypi:/home/pi/02_gps/curl-7.43.0/src# ./curl -V

curl 7.43.0 (armv7l-unknown-linux-gnueabihf) libcurl/7.43.0 OpenSSL/0.9.8y zlib/1.2.7

Protocols: dict file ftp ftps gopher http https imap imaps pop3 pop3s rtsp smb smbs smtp smtps telnet tftp

Features: Largefile NTLM NTLM_WB SSL libz UnixSockets

一個簡單的HTTPS GET 程式

#include <stdio.h>

#include <curl/curl.h>

#include <string.h>

#include <stdlib.h>

static char *replace(const char *in, const char *pattern, const char *by);

int main(void)

{

 CURL *curl = curl_easy_init();

 char *new_url;

 char *c_rep=" ";

 char *c_with="+";

 char request[]="https://www.googleapis.com/fusiontables/v2/query?sql=SELECT * from 1fV5mXuKgG5cCck1cAVQX0G7HVTjfdm1SqeYSdmXU&key=AIzaSyDz_-qvtMk7rVWi6NSJMTSv509Df4wTuOg";

 new_url=replace(request,c_rep,c_with);

  fprintf(stderr,"%s\n\n",request);

  if(curl) {

  CURLcode res;

  curl_easy_setopt(curl, CURLOPT_URL,new_url);

  res = curl_easy_perform(curl);

  curl_easy_cleanup(curl);

}

  free(new_url);

  return 0;

}

//replace 函式主要是將 URL 空白字元轉成 + 字元
//sql=SELECT * from  ==> sql=SELECT+*+from

static char *replace(const char *in, const char *pattern, const char *by)

{

    size_t outsize = strlen(in) + 1;

    // TODO maybe avoid reallocing by counting the non-overlapping occurences of pattern

    char *res = malloc(outsize);

    // use this to iterate over the output

    size_t resoffset = 0;

    char *needle;

    while (needle = strstr(in, pattern)) {

        // copy everything up to the pattern

        memcpy(res + resoffset, in, needle - in);

        resoffset += needle - in;

    

        // skip the pattern in the input-string

        in = needle + strlen(pattern);

        // adjust space for replacement

        outsize = outsize - strlen(pattern) + strlen(by);

        res = realloc(res, outsize);

        // copy the pattern

        memcpy(res + resoffset, by, strlen(by));

        resoffset += strlen(by);

    }

    // copy the remaining input

    strcpy(res + resoffset, in);

    return res;

}

程式執行結果