详解crifan的Python库：crifanLib.py

2.4. 网络方面的函数

#------------------------------------------------------------------------------
# download from fileUrl then save to fileToSave
# with exception support
# note: the caller should make sure the fileUrl is a valid internet resource/file
def downloadFile(fileUrl, fileToSave, needReport = False) :
    isDownOK = False;
    downloadingFile = '';

    #---------------------------------------------------------------------------
    # note: totalFileSize -> may be -1 on older FTP servers which do not return a file size in response to a retrieval request
    def reportHook(copiedBlocks, blockSize, totalFileSize) :
        #global downloadingFile
        if copiedBlocks == 0 : # 1st call : once on establishment of the network connection
            print 'Begin to download %s, total size=%d'%(downloadingFile, totalFileSize);
        else : # rest call : once after each block read thereafter
            print 'Downloaded bytes: %d' % ( blockSize * copiedBlocks);
        return;
    #---------------------------------------------------------------------------

    try :
        if fileUrl :
            downloadingFile = fileUrl;
            if needReport :
                urllib.urlretrieve(fileUrl, fileToSave, reportHook);
            else :
                urllib.urlretrieve(fileUrl, fileToSave);
            isDownOK = True;
        else :
            print "Input download file url is NULL";
    except urllib.ContentTooShortError(msg) :
        isDownOK = False;
    except :
        isDownOK = False;

    return isDownOK;
        

if dstPicFile and downloadFile(curUrl, dstPicFile) : 
    # replace old url with new url