Downloading multiple files from an FTP server files using Libcurl - c++

Question

I have used the following code to get to download all the files from the FTP Server
Steps followed are:
1. Creating a FTP list of File
getFTPList(string sHost, string sUser, string sPass, string sUri)
{
CURL *curl;
CURLcode res;
FILE *ftplister;
string host = "ftp://";
host += sHost;
host += "/sample/";
string furl = host + sUri;
string usrpwd = sUser;
usrpwd += ":";
usrpwd += sPass;
/* local file name to store the file as */
ftplister = fopen("ftp-list", "wb"); /* b is binary, needed on win32 */
curl = curl_easy_init();
if(curl) {
/* Get a file listing from sunet */
curl_easy_setopt(curl, CURLOPT_URL, furl.c_str() );
curl_easy_setopt(curl, CURLOPT_USERPWD, usrpwd.c_str());
curl_easy_setopt(curl, CURLOPT_FTPLISTONLY, TRUE);
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, &write_list);
curl_easy_setopt(curl, CURLOPT_WRITEDATA, ftplister);
res = curl_easy_perform(curl);
/* Check for errors */
if(res != CURLE_OK)
fprintf(stderr, "curl_easy_perform() failed: %s\n",
curl_easy_strerror(res));
/* always cleanup */
curl_easy_cleanup(curl);
}
fclose(ftplister); /* close the local file */
}
Use this list to download the files calling the download functions recursively
int main(){
FILE *ftpfile;
string line;
ftpfile = fopen("ftp-list", "r");
ifstream infile("ftp-list");
while ( getline(infile, line) )
{
string url, ofname, surl = "ftp://myhost/uploader/", sfname = "C:\\CNAP\\";
url = surl + line;
ofname = sfname +line;
cout<<url<<" "<<ofname<<endl;
char* theVal ;
char* theStr ;
theVal = new char [url.size()+1];
theStr = new char [ofname.size()+1];
strcpy(theVal, url.c_str());
strcpy(theStr, ofname.c_str());
downloadFile(theVal, theStr);
}
return 0;
}
Now the download function:
size_t write_data(void *ptr, size_t size, size_t nmemb, FILE *stream) {
size_t written;
written = fwrite(ptr, size, nmemb, stream);
return written;
}
void downloadFile(const char* url, const char* ofname)
{
CURL *curl;
FILE *fp;
CURLcode res;
curl = curl_easy_init();
if (curl){
fp = fopen(ofname,"wb");
curl_easy_setopt(curl, CURLOPT_URL, url);
curl_easy_setopt(curl, CURLOPT_USERPWD, "user:pass");
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data);
curl_easy_setopt(curl, CURLOPT_WRITEDATA, fp);
res = curl_easy_perform(curl);
curl_easy_cleanup(curl);
fclose(fp);
}
}
It works well when implemented but only to download text files or some files with texts, if I download an image or a docx or a a zip or rar or for that matter any file which is not text it fails, it fails to open after downloading (says invalid file).
I am not sure what am I missing, any help would be appreciated.
I know this is an inefficient way of coding, but I just need the downloads to be right (any file). Working on the efficiency is my next agenda.
PS: Used this method used here
Downloading multiple files with libcurl in C++
Thank you

Answer 1

The file when downloading needs to be opened as a binary file
fp = fopen(ofname,"wb");
Thank you for the help Rob

Answer 2

This is a guess.:
Try clearing the options CURLOPT_TRANSFERTEXT and CURLOPT_CRLF.
Refernce:
http://curl.haxx.se/libcurl/c/curl_easy_setopt.html

Answer 3

#include <stdio.h>
#include <curl/curl.h>
#include <curl/easy.h>
#include <string>
#include <iostream>
#include <fstream>
using namespace std;
size_t write_data(void *ptr, size_t size, size_t nmemb, FILE *stream);
void getFileList(
const string &strHost,
const string &strUri,
const string &strUser,
const string &strPassWord,
const string &strTargetFile
);
void downloadAllFiles(
const string &strFtpListFile,
const string &strHost,
const string &strUri,
const string &strUser,
const string &strPassWord,
const string &strSaveTargetFolder
);
int main(void)
{
string strHost = "ftp://192.168.0.1:22";
string strUri = "/cobus/test/";
string strUser = "cobus";
string strPassWord = "password";
string strTargetFile = "c:\\cobus\\ftpList.txt";
string strSaveDestFolder = "c:\\cobus\\";
getFileList(strHost, strUri, strUser, strPassWord, strTargetFile);
downloadAllFiles(
strTargetFile,
strHost,
strUri,
strUser,
strPassWord,
strSaveDestFolder
);
}
size_t write_data(void *ptr, size_t size, size_t nmemb, FILE *stream)
{
size_t written = fwrite(ptr, size, nmemb, stream);
return written;
}
void getFileList(const string &strHost, const string &strUri,
const string &strUser, const string &strPassWord, const string &strTargetFile)
{
CURL *curl;
CURLcode res;
FILE *ftplister;
string strSourceFullUri = strHost + strUri;
string strUserPwInfo = strUser + ":" + strPassWord;
/* local file name to store the file as */
ftplister = fopen(strTargetFile.c_str(), "wb"); /* b is binary, needed on win32 */
curl = curl_easy_init();
if(curl)
{
/* Get a file listing from sunet */
curl_easy_setopt(curl, CURLOPT_URL, strSourceFullUri.c_str() );
curl_easy_setopt(curl, CURLOPT_USERPWD, strUserPwInfo.c_str());
curl_easy_setopt(curl, CURLOPT_FTPLISTONLY, TRUE);
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, &write_data);
curl_easy_setopt(curl, CURLOPT_WRITEDATA, ftplister);
res = curl_easy_perform(curl);
/* Check for errors */
if(res != CURLE_OK)
fprintf(stderr, "curl_easy_perform() failed: %s\n",
curl_easy_strerror(res));
/* always cleanup */
curl_easy_cleanup(curl);
}
fclose(ftplister); /* close the local file */
}
void downloadAllFiles(const string &strFtpListFile, const string &strHost,
const string &strUri, const string &strUser, const string &strPassWord,
const string &strSaveDestFolder)
{
FILE *ftpFile = NULL;
string strFileName = "";
ifstream infile(strFtpListFile.c_str());
if(!infile.is_open())
{
cerr << "can not open ftpList.txt" << endl;
return ;
}
/* ftpList.txt get data, line by line, processing */
while(getline(infile, strFileName))
{
CURL *curl;
FILE *destFilePath;
CURLcode res;
curl = curl_easy_init();
if (curl)
{
destFilePath = fopen((strSaveDestFolder+strFileName).c_str(),"wb");
curl_easy_setopt(curl, CURLOPT_URL, (strHost+strUri+strFileName).c_str());
curl_easy_setopt(curl, CURLOPT_USERPWD, (strUser+":"+strPassWord).c_str());
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data);
curl_easy_setopt(curl, CURLOPT_WRITEDATA, destFilePath);
res = curl_easy_perform(curl);
curl_easy_cleanup(curl);
fclose(destFilePath);
}
}// end while
}
I expressed as much as possible to see at once the contents of the Vivian Lobo.
I tried to test to make statements Vivian Lobo. It is good working.
stackOverFlow is hard to write code.
And how can I comment to Vivian lobo article?