图像通过XML从iPhone发送到App Engine

我想从我的iPhone应用程序发送一个小图像以及一些XML信息到App Engine。我在路上的某个地方遇到了问题。没有错误，并且数据正在被转移到数据存储查看器中的Blob条目中，但App Engine上的blob文件未出现在Blob查看器中。我怀疑图片在App Engine中的某个转换中混乱，或者未被存储为App Engine中的正确类型。你怎么看？图像通过XML从iPhone发送到App Engine

在iPhone上，这里是有关部分编码图像（使用标准base64Encoding功能），并将其添加到GDataXMLElement，然后把它加入到一个GDataXMLDoc和发送与ASIHTTPRequest：

NSString *dataString = [self.data base64Encoding]; 
GDataXMLElement *tempXMLElement = [GDataXMLElement elementWithName:@"data" stringValue: dataString]; 
[imageElement addChild: tempXMLElement];

在ASIHTTPRequest部分：

ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL: url]; 
[request setDelegate: self]; 
[request addRequestHeader:@"User-Agent" value: [NSString stringWithFormat:@"MyApp:%@", version]]; 
[request addRequestHeader:@"Content-Type" value:@"text/xml"]; 
[request setShouldStreamPostDataFromDisk:YES]; 
[request appendPostDataFromFile: path]; 
[request start];

在App Engine上的Python（最有可能在那里一个问题在于）：

image_data_xml_element = image_xml_node.getElementsByTagName("data")[0] 
image_data_base64_unicode = image_data_xml_element.firstChild.data 
image_data_base64_ascii = image_data_unicode.encode("utf8") 
image_data_string = binascii.a2b_base64(image_data_base64_ascii) 
new_image.data = db.Blob(image_data_string)

此外，我曾尝试：

image_data_xml_element = image_xml_node.getElementsByTagName("data")[0] 
image_data_base64_unicode = image_data_xml_element.firstChild.data 
image_data_string = base64.b64decode(image_data_base64_unicode) 
new_image.data = db.Blob(image_data_string)

编辑：为了完整起见，这里是我使用的Objective-C的base64库 - 它看起来并不像我所期待的：

static const char encodingTable[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz/"; 
- (NSString *)base64Encoding;{ 
    if ([self length] == 0) 
     return @""; 

    char *characters = malloc((([self length] + 2)/3) * 4); 
    if (characters == NULL) 
     return nil; 
    NSUInteger length = 0; 
    NSUInteger i = 0; 
    while (i < [self length]){ 
     char buffer[3] = {0,0,0}; 
     short bufferLength = 0; 
     while (bufferLength < 3 && i < [self length]) 
      buffer[bufferLength++] = ((char *)[self bytes])[i++]; 

     // Encode the bytes in the buffer to four characters, including padding "=" characters if necessary. 
     characters[length++] = encodingTable[(buffer[0] & 0xFC) >> 2]; 
     characters[length++] = encodingTable[((buffer[0] & 0x03) << 4) | ((buffer[1] & 0xF0) >> 4)]; 
     if (bufferLength > 1) 
      characters[length++] = encodingTable[((buffer[1] & 0x0F) << 2) | ((buffer[2] & 0xC0) >> 6)]; 
     else characters[length++] = '='; 
     if (bufferLength > 2) 
      characters[length++] = encodingTable[buffer[2] & 0x3F]; 
     else characters[length++] = '=';  
    } 

    return [[[NSString alloc] initWithBytesNoCopy:characters length:length encoding:NSASCIIStringEncoding freeWhenDone:YES] autorelease]; 
}

来源

2010-09-11 Ryan Bavetta