IOS And WCF Story

研究IOS上传到WCF图片的小功能，WCF实现服务端的文件上传的例子很多，单独实现IOS发送图片的例子也很多，但是两个结合起来的就很少了。
可以通过base64来上传图片，这个方式比较简单，但是我想要的是通过网络流来传送，这样以后IOS发送任何的文件，服务器不需要修改就能直接来用。想法很简单，但是历程很辛苦。。。

IOS发送

首先研究一下IOS端的图片传输，我用的网络框架是AFNetWorking，附上代码

NSString *filename=@"test.jpg";
AFHTTPRequestOperationManager *AFManager=[[AFHTTPRequestOperationManager alloc]initWithBaseURL:[NSURL URLWithString:@FileTranUrl]];
AFHTTPRequestOperation *operation=[AFManager POST:path parameters:nil constructingBodyWithBlock:^(id<AFMultipartFormData> formdata){[formdata appendPartWithFileData:imagedata name:name fileName:filename mimeType:@"image/jpeg"];} success:^(AFHTTPRequestOperation *operation, id responSEObject) {
    if (success) {
        success(operation,responseObject);
    }
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
    if (failure) {
        failure(operation,error);
    }
}];

imagedata是image转换为NSdata后的值。

这里的代码看起来很多，其实很简单，关键只有一处就是

[formdata appendPartWithFileData:imagedata name:name fileName:filename mimeType:@"image/jpeg"];

AFMultipartFormData 做了什么呢？

查看它的appendPartWithFileData:name:filename:mimeType:源代码，我们可以看到

- (void)appendPartWithFileData:(NSData *)data
                      name:(NSString *)name
                  fileName:(NSString *)fileName
                  mimeType:(NSString *)mimeType
{
  NSParameterAssert(name);
  NSParameterAssert(fileName);
  NSParameterAssert(mimeType);

  NSMutableDictionary *mutableHeaders = [NSMutableDictionary dictionary];
  [mutableHeaders setValue:[NSString stringWithFormat:@"form-data; name=\"%@\"; filename=\"%@\"", name, fileName] forKey:@"Content-Disposition"];
  [mutableHeaders setValue:mimeType forKey:@"Content-Type"];

  [self appendPartWithHeaders:mutableHeaders body:data];
}

multableHeaders包含了name,filename,mimeType再次查看最后一个方法的定义

 - (void)appendPartWithHeaders:(NSDictionary *)headers
                     body:(NSData *)body
{
    NSParameterAssert(body);

    AFHTTPBodyPart *bodyPart = [[AFHTTPBodyPart alloc] init];
    bodyPart.stringEncoding = self.stringEncoding;
    bodyPart.headers = headers;
    bodyPart.boundary = self.boundary;
    bodyPart.bodyContentLength = [body length];
    bodyPart.body = body;

    [self.bodyStream appendHTTPBodyPart:bodyPart];
}

[self.bodyStream appendHTTPBodyPart:bodyPart];看到这里的时候我们已经明白了，以上所有包含的数据全部放到网络流里了。为什么要查看这些呢？因为WCF需要契约定义，我们不知道AFNetwork发送的时候我们应该用什么契约来接受这个方法。

WCF接受

通过上面的分析，我们已经大概知道契约的定义了

void(Stream requestStream)

WCF在接受数据之前还需要进行配置，在

<system.serviceModel>
<bindings>
  <webHttpBinding>
    <binding name="WebConfiguration"
             maxBufferSize="65536"
             maxReceivedMessageSize="2000000000"
             transferMode="Streamed">
    </binding>
  </webHttpBinding>
  </bindings>

<services>      
  <!--文件服务-->
  <service name="WcfServiceForIOS.ServiceForIOSFile" behaviorConfiguration="ServiceBehavior">
    <endpoint address=""  binding="webHttpBinding" behaviorConfiguration="web"   bindingConfiguration="WebConfiguration"  contract="WcfServiceForIOS.IServiceForIOSFile" />
  </service>
  
</services>
<behaviors>
  <endpointBehaviors>
    <behavior name="web">
      <webHttp />
    </behavior>
  </endpointBehaviors>
  <serviceBehaviors>
    <behavior name="ServiceBehavior">
      <serviceMetadata httpGetEnabled="true" />
      <serviceDebug includeExceptionDetailInFaults="false" />
    </behavior>      
  </serviceBehaviors>
</behaviors>
</system.serviceModel>

尝试实现契约的主要代码

using (targetStream = new FileStream(filePathAndName, FileMode.Create, Fileaccess.Write, FileShare.None))
{
   const int bufferLen = 4096;
   Byte[] buffer = new Byte[bufferLen];
  int count = 0;

   while ((count = sourceStream.Read(buffer, 0, bufferLen)) > 0)
    {
     targetStream.Write(buffer, 0, count);
     filesize += count;
    }
    targetStream.Close();
    sourceStream.Close();                  
           
             
}

等IOS上传图片后，可以在相应的文件夹中找到生成的图片，但是不幸的是我们无法打开，提示图片损坏太大。用NotePad++打开这个文件流，可以看到以下代码

--Boundary+4AA85CFEE4A1D140
Content-Disposition: form-data; name="file"; filename="test.jpg"
Content-Type: image/jpeg
（乱码，目测是图片的数据流）
--Boundary+4AA85CFEE4A1D140--

是不是和发送时候的很眼熟，这样和前面的分析就对上了，传输过来的文件流是包含图片的信息和图片的数据。需要分开处理。
处理方法和web发送的form-data是一样的，先编码为string，通过正则表达取出各个属性值

 private void Parse(Stream stream, Encoding encoding)
    {
        this.Success = false;

        // Read the stream into a byte array
        byte[] data = ToByteArray(stream);
        requestData = data;

        // Copy to a string for header parsing
        string content = encoding.GetString(data);

        // The first line should contain the delimiter
        int delimiterEndIndex = content.IndexOf("\r\n");

        if (delimiterEndIndex > -1)
        {
            string delimiter = content.Substring(0, content.IndexOf("\r\n"));

            // Look for Content-Type
            Regex re = new Regex(@"(?<=Content\-Type:)(.*?)(?=\r\n\r\n)");
            Match contentTypeMatch = re.Match(content);

            // Look for filename
            re = new Regex(@"(?<=filename\=\"")(.*?)(?=\"")");
            Match filenameMatch = re.Match(content);

            // Did we find the required values?
            if (contentTypeMatch.Success && filenameMatch.Success)
            {
                // Set properties
                this.ContentType = contentTypeMatch.Value.Trim();
                this.Filename = filenameMatch.Value.Trim();

                // Get the start & end indexes of the file contents
                int startIndex = contentTypeMatch.Index + contentTypeMatch.Length + "\r\n\r\n".Length;

                byte[] delimiterBytes = encoding.GetBytes("\r\n" + delimiter);
                int endIndex = IndexOf(data, delimiterBytes, startIndex);

                int contentLength = endIndex - startIndex;

                // Extract the file contents from the byte array
                byte[] fileData = new byte[contentLength];

                Buffer.BlockCopy(data, startIndex, fileData, 0, contentLength);

                this.FileContents = fileData;
                this.Success = true;
            }
        }
    } 

取出各个段后就能用来存文件了

参考连接

• stackOverFlow_1
  
• stackOverFlow_2
  
• 逆时针の风Cnblog