PureBasic Forums - English

Posted: **Tue Apr 08, 2014 6:31 pm**

I want to present another solution which uses libcurl.dylib and imports the required functions. The libcurl.dylib doesn't need to be installed because it is contained in /usr/lib.

Code: Select all

EnableExplicit

#ServerFile = "http://purebasic.com/documentation/PureBasicSmall.pdf"

#CURL_ERROR_SIZE          =   256
#CURLOPT_ERRORBUFFER      = 10010
#CURLOPT_NOPROGRESS       =    43
#CURLOPT_PROGRESSFUNCTION = 20056
#CURLOPT_URL              = 10002
#CURLOPT_WRITEFUNCTION    = 20011

ImportC "/usr/lib/libcurl.dylib"
  curl_easy_cleanup(*CurlSession)
  curl_easy_init()
  curl_easy_setopt(*CurlSession, Option.I, Parameter.I)
  curl_easy_strerror(ErrorNumber.I)
  curl_easy_perform(*CurlSession) 
EndImport

Define ClientFile.S = GetTemporaryDirectory() + "PureBasicSmall.pdf"
Define i.I
Define ReceivedData.S
Define ServerFile.S

ProcedureC DataReceivedCallback(*Data, Size.I, NMemb.I, *UserData)
  WriteData(0, *Data, Size * NMemb)

  ProcedureReturn Size * NMemb
EndProcedure

ProcedureC ProgressCallback(*ProgressData, DownloadTotal.D, DownloadNow.D,
  UploadTotal.D, UploadNow.D)
  Debug StrD(DownloadNow) + " Bytes from " + StrD(DownloadTotal) +
    " Bytes have been downloaded"
EndProcedure

Procedure SetCurlOption(CurlSession.I, Option.I, Parameter.I)
  CompilerSelect #PB_Compiler_Processor
    CompilerCase #PB_Processor_x86
      curl_easy_setopt(CurlSession, Option, Parameter)
    CompilerCase #PB_Processor_x64
      !EXTERN _curl_easy_setopt
      !MOV    RDI,QWORD [p.v_CurlSession]
      !MOV    RSI,QWORD [p.v_Option]
      !MOV    RDX,QWORD [p.v_Parameter]
      !CALL   _curl_easy_setopt
  CompilerEndSelect
EndProcedure

Procedure DownloadFile(URL.S)
  Shared ReceivedData.S
  
  Protected CurlSession.I
  Protected ErrorCode.I
  Protected ErrorMsg.S = Space(#CURL_ERROR_SIZE)
  Protected *ErrorMsgBuffer = AllocateMemory(#CURL_ERROR_SIZE)
  Protected Result.I = #False
  
  CurlSession = curl_easy_init()
  
  If CurlSession
    SetCurlOption(CurlSession, #CURLOPT_URL, @URL)
    SetCurlOption(CurlSession, #CURLOPT_WRITEFUNCTION, @DataReceivedCallback())
    SetCurlOption(CurlSession, #CURLOPT_ERRORBUFFER, *ErrorMsgBuffer)
    SetCurlOption(CurlSession, #CURLOPT_PROGRESSFUNCTION, @ProgressCallback())
    SetCurlOption(CurlSession, #CURLOPT_NOPROGRESS, #False)
    
    ErrorCode = curl_easy_perform(CurlSession)
    
    If ErrorCode = 0
      Result = #True
    Else
      CompilerIf #PB_Compiler_Unicode
        ErrorMsg = Space(StringByteLength(PeekS(*ErrorMsgBuffer, -1,
          #PB_Ascii), #PB_Unicode))
        PokeS(@ErrorMsg, PeekS(*ErrorMsgBuffer, -1, #PB_Ascii), -1, #PB_Unicode)
      CompilerElse
        ErrorMsg = PeekS(*ErrorMsgBuffer)
      CompilerEndIf

      If Trim(ErrorMsg) = ""
        CompilerIf #PB_Compiler_Unicode
          ErrorMsg = Space(StringByteLength(PeekS(curl_easy_strerror(ErrorCode),
            -1, #PB_Ascii), #PB_Unicode))
          PokeS(@ErrorMsg, PeekS(curl_easy_strerror(ErrorCode), -1, #PB_Ascii), -1,
            #PB_Unicode)
        CompilerElse
          ErrorMsg = PeekS(curl_easy_strerror(ErrorCode))
        CompilerEndIf
      EndIf

      MessageRequester("Error", ErrorMsg)
    EndIf
    
    FreeMemory(*ErrorMsgBuffer)
    curl_easy_cleanup(CurlSession)
  EndIf

  ProcedureReturn Result
EndProcedure

If OpenFile(0, ClientFile)
  If #PB_Compiler_Unicode
    ServerFile = Space(StringByteLength(#ServerFile))
    PokeS(@ServerFile, #ServerFile, -1, #PB_Ascii)
  Else
    ServerFile = #ServerFile
  EndIf

  If DownloadFile(ServerFile)
    MessageRequester("HTTP-Download", "The file" + #CR$ + #CR$ + #ServerFile + #CR$ + #CR$ + "was downloaded successfully and stored as" + #CR$ + #CR$ + ClientFile)
  EndIf

  CloseFile(0)
EndIf

Update 1: I have modified the code to work in both ASCII and Unicode mode.
Update 2: I have added the new procedure SetCurlOption() which uses x64 assembly instructions (when compiled on a x64 processor) to correctly move the arguments into the correct registers and call curl_easy_setopt(). I have verified this code to successfully run on MacOS X Snow Leopard and Mavericks in x86 and x64 mode and in both ASCII and Unicode mode.

Posted: **Tue Apr 08, 2014 8:55 pm**

Shardik wrote:I want to present another solution which uses libcurl.dylib and imports the required functions. Currently it only works with the PB x86 compiler and with Unicode mode disabled (the program recognizes these conditions and displays an info message). I have tested the program with OS X 10.6.8 (Snow Leopard). The libcurl.dylib doesn't need to be installed because it is contained in /usr/lib.
Code: Select all
...

Great piece of code Shardik! Unfortunately I can't test it right now because I have just the x64 version of PureBasic installed. Can you explain why your code works only on x86 platform and without unicode? Is it a limitation of the libcurl library itself?

Thanks!

Posted: **Wed Apr 09, 2014 4:28 pm**

ergrull0 wrote:Can you explain why your code works only on x86 platform and without unicode? Is it a limitation of the libcurl library itself?

To implement Unicode I was just too lazy...

I have therefore modified the above code to work in both ASCII and Unicode mode.

The culprit for only working when compiled to x86 code is the PB compiler. PB doesn't support variable argument functions which libcurl requires. For a solution you have to program a customized C wrapper. You may take a look into this thread:

Fred wrote:You can't call such variable argument functions in PB directly, you will need a wrapper.

Fred wrote:PB doesn't support this notation, so args are arbitrary pushed on the stacks on x86 and using regs on x64, but the interpretation depends of the type. Better write a small wrapper in C to handle that.

Fred's last statement would mean that even the x86 version is working only by luck, but I never experienced any problems with my x86 programs using libcurl on Windows XP SP3, Windows Server 2000, Windows 7 SP1, different Linux distributions and MacOS X Snow Leopard...

It's not a problem of the libcurl version contained in MacOS X which is compiled as a universal binary for x64, x86 and PPC. You may proof this with the following terminal command:

Code: Select all

file /usr/lib/libcurl.dylib

Posted: **Wed Apr 09, 2014 5:34 pm**

Shardik wrote:[...]The culprit for only working when compiled to x86 code is the PB compiler. PB doesn't support variable argument functions which libcurl requires[...]

So, just to clarify my mind, the problem is that the curl_easy_setopt() function requires different types of parameters (a function pointer, a long etc...) based on the CURLOPT_[...] option, and this kind of "variability" is not supported by PB. Am I right?

Posted: **Wed Apr 09, 2014 8:18 pm**

ergrull0 wrote:So, just to clarify my mind, the problem is that the curl_easy_setopt() function requires different types of parameters (a function pointer, a long etc...) based on the CURLOPT_[...] option, and this kind of "variability" is not supported by PB. Am I right?

Yes, you are right!

Posted: **Sat Apr 19, 2014 2:24 pm**

I have modified my example code from above to also work with PB's x64 compiler. I have added the new procedure SetCurlOption() which uses x64 assembly instructions (when compiled on a x64 processor) to correctly move the arguments into the correct registers and call curl_easy_setopt(). I have verified this code to successfully run on MacOS X Snow Leopard and Mavericks in x86 and x64 mode and in both ASCII and Unicode mode.

PureBasic Forums - English

RunProgram(): Weird ReadProgramString() behaviour?

Re: RunProgram(): Weird ReadProgramString() behaviour?

Re: RunProgram(): Weird ReadProgramString() behaviour?

Re: RunProgram(): Weird ReadProgramString() behaviour?

Re: RunProgram(): Weird ReadProgramString() behaviour?

Re: RunProgram(): Weird ReadProgramString() behaviour?

Re: RunProgram(): Weird ReadProgramString() behaviour?