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    How to download a file from the internet? [SOLVED]

    SDK Help
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    • H
      Helper
      last edited by

      On 06/10/2014 at 12:33, xxxxxxxx wrote:

      You still need the .cdl files and your usual plugin stuff.
      The .cdl files are for running your plugin.
      The libcurl.dll file is how C4D itself finds the curl libraries.

      This is my understanding of how it works:
      When you set up the curl paths in VS. You're telling VS where to find the curl libraries. But you haven't told C4D (the program) where to find them.
      Maxon has set up the c4d program to look for the C4D based .dll files in a specific folder/folders. So that our plugins can make use of them.
      The C4D program is basically a plugin reader program.
      It grabs the .dlls from where it was told to grab them. The ones that ship with it, and the ones built in and our plugins.
      When you bring in an alien .dll file. C4D has not been told where and how to use it.
      But when C4D launches. It's able to read a .dll file if it's in the MAXON folder.

      As an example. QT is a very popular library people use for GUI stuff.
      The various programs they use QT libraries on have no clue what a QT.dll is. QT.dll is an alien file.
      So in addition to telling VS how to link the QT libraries to the code they're writing. They also have to put a copy of the .dll's in the source files when they package up their program to send to the users.
      If you look at the files that people include in their programs. If it uses a QT based GUI. And the they did not compile QT as static. Then you should see somewhere in the source files a few QT.dll files.
      In c4d. The place where these alien .dll files go is the MAXON folder.

      I think most of that is correct. But don't take it as gospel.
      I'm still learning how things work myself.

      -ScottA

      Edit- There's probably a way to put the libcurl.dll in your plugin folder rather than the MAXON folder.
      And have C4D somehow read it from there. But I have never done it. People like Robert might know how.

      1 Reply Last reply Reply Quote 0
      • H
        Helper
        last edited by

        On 06/10/2014 at 13:47, xxxxxxxx wrote:

        Umm...hmmm. Confused
        I just re-wrote the plugin from scratch. And this time it runs fine if I put the libcurl.dll file in my plugin folder.
        I have no idea why it wouldn't run before. So you might not need to put libcurl.dll in the MAXON folder.

        Sorry about any confusion Rui.
        This is the first time I've fooled around with .dll files in my c4d plugins.

        -ScottA

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        • H
          Helper
          last edited by

          On 06/10/2014 at 14:10, xxxxxxxx wrote:

          You can statically compile libCurl and then link the static lib. That way you do not need to include the dll when you ship your plugin.

          1 Reply Last reply Reply Quote 0
          • H
            Helper
            last edited by

            On 06/10/2014 at 14:41, xxxxxxxx wrote:

            Could it be that that is what is happening when I compile in Xcode?
            My plugin is running perfectly on my Mac, accessing the internet and checking for the file in a protected folder.
            And I haven't copied any library into my plugins folder or to the Maxon folder.

            1 Reply Last reply Reply Quote 0
            • H
              Helper
              last edited by

              On 06/10/2014 at 15:30, xxxxxxxx wrote:

              That sounds like a logical assumption to me.

              It's nice that Macs have that set up for you. PC's require most things to be installed by hand.
              On the other hand. If someone does all of the work for you. You never learn how to do it yourself.
              Which is why Python is both wonderful & evil.

              -ScottA

              1 Reply Last reply Reply Quote 0
              • H
                Helper
                last edited by

                On 06/10/2014 at 16:37, xxxxxxxx wrote:

                But, for the specific case of plugins it is so nice.
                I'm having all this trouble because I devised a method to protect my plugins. It is not perfect (no method is) but it makes me more in control and makes life harder for hackers.
                It was relatively simple to implement on my Mac. It is a nuisance that it proves to be so complicated on Windows (never really liked Windows very much and this only makes it worse 😞 )

                1 Reply Last reply Reply Quote 0
                • H
                  Helper
                  last edited by

                  On 07/10/2014 at 07:38, xxxxxxxx wrote:

                  Out of curiosity.
                  How are you converting the curl output to a C4D String type result in your Mac version?
                  The callback method I posted works. But it looks kind of ugly to me. And I'm wondering if there's a simpler way.

                  -ScottA

                  1 Reply Last reply Reply Quote 0
                  • H
                    Helper
                    last edited by

                    On 07/10/2014 at 07:58, xxxxxxxx wrote:

                    Here is my code:

                      
                    //   
                    // access_url.cpp   
                    // PolyPaintTag   
                    //   
                    // Created by Rui Batista on 6/10/14.   
                      
                    #include "access_url.h"   
                      
                    #ifdef _WIN32   
                    #include <curl.h>   
                    #endif   
                      
                    #ifndef _WIN32   
                    #include <curl/curl.h>   
                    #endif   
                      
                    #include <string>   
                      
                    using namespace std;   
                      
                    // ***************************************************************   
                      
                    struct MemoryStruct {   
                         char* memory;   
                         size_t size;   
                    };   
                      
                    // ***************************************************************   
                      
                    static size_t   
                    WriteMemoryCallback(void *contents, size_t size, size_t nmemb, void *userp)   
                    {   
                         size_t realsize = size * nmemb;   
                         struct MemoryStruct *mem = (struct MemoryStruct * )userp;   
                            
                         mem->memory = (char* )realloc(mem->memory, mem->size + realsize + 1);   
                         if(mem->memory == NULL) {   
                              /* out of memory! */   
                              printf("not enough memory (realloc returned NULL)\n");   
                              return 0;   
                         }   
                            
                         memcpy(&(mem->memory[mem->size]), contents, realsize);   
                         mem->size += realsize;   
                         mem->memory[mem->size] = 0;   
                            
                         return realsize;   
                    }   
                      
                    // ***************************************************************   
                      
                    bool check_online(string folder,string reg, string username)   
                    {   
                         CURL *curl;   
                         CURLcode res;   
                            
                         char *passcode=new char[usrpass.length()+1];   
                         for(long i=0;i<usrpass.length()+1;i++)   
                         {   
                              passcode[i]=usrpass[i];   
                              passcode[i+1]='\0';   
                         }   
                            
                         bool success=true;   
                            
                         struct MemoryStruct chunk;   
                         chunk.memory = (char* ) malloc(1); /* will be grown as needed by the realloc above */   
                         chunk.size = 0;    /* no data at this point */   
                            
                         curl = curl_easy_init();   
                         if(curl) {   
                              string baseurl="www.my_url.com";   
                              string usrpass="username:password";   
                                 
                              char *the_url=new char[baseurl.length()+1];   
                              strcpy(the_url, baseurl.c_str());   
                                 
                              curl_easy_setopt(curl, CURLOPT_URL, the_url);   
                              curl_easy_setopt(curl, CURLOPT_HTTPAUTH, CURLAUTH_ANY);   
                              curl_easy_setopt(curl, CURLOPT_USERPWD , passcode);   
                              curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);   
                              curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void * )&chunk;);   
                              curl_easy_setopt(curl, CURLOPT_USERAGENT, "libcurl-agent/1.0");   
                                 
                              /* Perform the request, res will get the return code */   
                              res = curl_easy_perform(curl);   
                                 
                              /* always cleanup */   
                              curl_easy_cleanup(curl);   
                                 
                              if (chunk.size!=10)   
                                   success=false;   
                              else   
                                   if(chunk.memory)   
                                   {   
                                        char *b=new char[2];   
                                        for(long i=0;i<10;i++)   
                                        {   
                                             string a=reg.substr(i,1);   
                                             b[0]=chunk.memory[i];   
                                             if (a!=b) success=false;   
                                        }   
                                           
                                        free(chunk.memory);   
                                   }   
                                 
                              delete [] the_url;   
                                 
                                 
                              /* Check for errors */   
                              if(res != CURLE_OK) success=false;   
                         }   
                            
                         delete [] passcode;   
                            
                            
                         return success;   
                    }   
                    

                    I changed a few things to protect my methods of checking the serialization.
                    However, you end up with a struct containing the bytes that were read and a count of the bytes read.
                    Assuming the chunk is a struct of type MemoryStruct, I guess it is just a matter of doing something like:

                      
                    char *my_string=new char[chunk.size+1];   
                    for(long i=0;i<chunk.size;i++)   
                    {   
                         my_string[i]=chunk.memory[i];   
                         my_string[i+1]='\0';   
                    }
                    
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                    • H
                      Helper
                      last edited by

                      On 07/10/2014 at 08:06, xxxxxxxx wrote:

                      Ok. Thanks.
                      You're using the same callback.
                      I was just curious if you were doing it a different way.

                      Are you done now?
                      All problems solved?

                      -ScottA

                      1 Reply Last reply Reply Quote 0
                      • H
                        Helper
                        last edited by

                        On 07/10/2014 at 08:15, xxxxxxxx wrote:

                        I had to pause for a while due to "real-life" work 😉
                        But I was getting all the errors when compiling for Win32.
                        When I compiled for x86, all errors stopped. I still have to test out.
                        Just picture this: I finally compiled without the errors and, all of a sudden, the phone rings and a complex and urgent illustration just arrives.
                        Damn!!! I must finish it to get back to my plugin (I can't have all the required apps opened for the illustration and Windows, at the same time)
                        Oh, by the way, do I only need to compile for x86?
                        Otherwise, I will have to install another version of curl also and do some conditional compiling 😞

                        1 Reply Last reply Reply Quote 0
                        • H
                          Helper
                          last edited by

                          On 07/10/2014 at 08:29, xxxxxxxx wrote:

                          I think you'll need both.

                          When I tried to use my 32bit version of curl in a 64 bit C4D plugin. That's when I got strange unresolved errors from the init() function.
                          So I'm guessing that you'll need to have both versions of curl built. And then point to the bits version of curl that matches your C4D plugin bits version.

                          -ScottA

                          1 Reply Last reply Reply Quote 0
                          • H
                            Helper
                            last edited by

                            On 07/10/2014 at 08:43, xxxxxxxx wrote:

                            Oh... so much more complicated in Windows 😞
                            How can I query for which version is being compiled. What are the preprocessor definitions?

                            (in the meanwhile, I have to go and finish my illustration).

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                            • H
                              Helper
                              last edited by

                              On 07/10/2014 at 09:25, xxxxxxxx wrote:

                              I've never used them.
                              But this is what I'm seeing on stack overflow about it:

                              #if _WIN64   
                              #include <windows.h>  
                              #include <your x64 curl folder here>  
                                
                              #else  
                              #include <windows.h>  
                              #include <your Win32 curl folder here>  
                              #endif
                              

                              -ScottA

                              1 Reply Last reply Reply Quote 0
                              • H
                                Helper
                                last edited by

                                On 07/10/2014 at 11:31, xxxxxxxx wrote:

                                Ok, just had a little time to test this and when I start Cinema4D in Windows with my plugin in the plugin folder, I get:

                                The program can't start because libcurl.dll is missing from your computer. Try reinstalling the program to fix the problem.

                                When I hit OK, Cinema4D starts but, of course my plugin doesn't gets loaded.
                                I tried to place the libcurl.dll next to the Cinema4D executable and the same happens. I also tried to place the libcurl.dll in my plugin folder but the same happens 😞
                                This is getting quite frustrating.

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                                • H
                                  Helper
                                  last edited by

                                  On 07/10/2014 at 11:40, xxxxxxxx wrote:

                                  make sure you are placing the "correct" libcurl.dll !!!. if you compile with 64 bit libraries, then you will need to put 64 bit dlls, or they won't get "seen"

                                  1 Reply Last reply Reply Quote 0
                                  • H
                                    Helper
                                    last edited by

                                    On 07/10/2014 at 12:20, xxxxxxxx wrote:

                                    Ok, placed the correct libcurl.dll in the Cinema 4D folder.
                                    Started Cinema 4D, and it told me that the libssh2.dll was missing.
                                    I also added that to the Cinema 4D folder.
                                    Started Cinema 4D again. Now it is asking for MSVCR120.dll
                                    I can't even find that .dll

                                    1 Reply Last reply Reply Quote 0
                                    • H
                                      Helper
                                      last edited by

                                      On 07/10/2014 at 12:25, xxxxxxxx wrote:

                                      MSVCR120.dll should be installed with VS 2013 , it is Microsoft Visual C++ compiler release 12, you can download it from google

                                      1 Reply Last reply Reply Quote 0
                                      • H
                                        Helper
                                        last edited by

                                        On 07/10/2014 at 12:50, xxxxxxxx wrote:

                                        Thank you, MohamedSakr.
                                        I did found it online.
                                        Ok, now Cinema 4D starts without errors. But my plugin doesn't even start.
                                        I placed GePrint's all over the place, mainly in the main.cpp, even before calling all my serialization stuff and nothing gets printed in the Console.

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                                        • H
                                          Helper
                                          last edited by

                                          On 07/10/2014 at 12:53, xxxxxxxx wrote:

                                          this needs code revision 🙂, test it in a step by step way, so GePrint in the plugin init function to check, test print after every line, till you find which line stops the plugin

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                                          • H
                                            Helper
                                            last edited by

                                            On 07/10/2014 at 12:55, xxxxxxxx wrote:

                                            a better approach "but in your case this will look much harder" , compile in "debug" , and step by step, this will need you to learn how debugging work in C++ "and specially in Visual Studio"

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