NSData和iOS上的POST上传图像

Question

我一直在梳理很多关于在iOS上通过POST上传图片的帖子.尽管有关此主题的大量信息,但我无法正确上传从我的iPhone模拟器照片库中获取的JPEG数据.数据一旦在服务器上,就只是一串巨大的十六进制数据.NSData不应该只是一个字节流吗？我不知道所有的十六进制是什么,或者为什么这个代码似乎适用于其他所有人.

这是有问题的代码:

-(void)uploadWithUserLocationString:(NSString*)userLocation{
NSString *urlString = @"http://some.url.com/post";

// set up the form keys and values (revise using 1 NSDictionary at some point - neater than 2 arrays)
NSArray *keys = [[NSArray alloc] initWithObjects:@"auth",@"text",@"location",nil];
NSArray *vals = [[NSArray alloc] initWithObjects:self.authToken,self.textBox.text,userLocation,nil];

// set up the request object
NSMutableURLRequest *request = [[[NSMutableURLRequest alloc] init] autorelease];
[request setURL:[NSURL URLWithString:urlString]];
[request setHTTPMethod:@"POST"];

//Add content-type to Header. Need to use a string boundary for data uploading.
NSString *boundary = [NSString stringWithString:@"0xKhTmLbOuNdArY"];
NSString *contentType = [NSString stringWithFormat:@"multipart/form-data; boundary=%@",boundary];
[request addValue:contentType forHTTPHeaderField: @"Content-Type"];

//create the post body
NSMutableData *body = [NSMutableData data];
[body appendData:[[NSString stringWithFormat:@"--%@\r\n",boundary] dataUsingEncoding:NSASCIIStringEncoding]];

//add (key,value) pairs (no idea why all the \r's and \n's are necessary ... but everyone seems to have them)
for (int i=0; i<[keys count]; i++) {
    [body appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"%@\"\r\n\r\n",[keys objectAtIndex:i]] dataUsingEncoding:NSASCIIStringEncoding]];
    [body appendData:[[NSString stringWithFormat:@"%@",[vals objectAtIndex:i]] dataUsingEncoding:NSASCIIStringEncoding]];
    [body appendData:[[NSString stringWithFormat:@"\r\n--%@\r\n",boundary] dataUsingEncoding:NSASCIIStringEncoding]];
}
[body appendData:[[NSString stringWithString:@"Content-Disposition: form-data; name=\"image\"\r\n"] dataUsingEncoding:NSASCIIStringEncoding]];
[body appendData:[[NSString stringWithString:@"Content-Type: application/octet-stream\r\n\r\n"] dataUsingEncoding:NSASCIIStringEncoding]];
[body appendData:[NSData dataWithData:self.imageData]];
[body appendData:[[NSString stringWithFormat:@"\r\n--%@--\r\n",boundary] dataUsingEncoding:NSASCIIStringEncoding]];

// set the body of the post to the reqeust
[request setHTTPBody:body];

// make the connection to the web
NSData *returnData = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];
NSString *returnString = [[NSString alloc] initWithData:returnData encoding:NSUTF8StringEncoding];

NSLog(returnString);
[keys release];
[vals release];
}

谢谢你的时间.

Answer 1

此代码适用于我的应用.如果您不使用ARC,则需要修改代码以释放任何已分配的内容.

// create request
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init];                                    
[request setCachePolicy:NSURLRequestReloadIgnoringLocalCacheData];
[request setHTTPShouldHandleCookies:NO];
[request setTimeoutInterval:30];
[request setHTTPMethod:@"POST"];

// set Content-Type in HTTP header
NSString *contentType = [NSString stringWithFormat:@"multipart/form-data; boundary=%@", boundary];
[request setValue:contentType forHTTPHeaderField: @"Content-Type"];

// post body
NSMutableData *body = [NSMutableData data];

// add params (all params are strings)
for (NSString *param in _params) {
    [body appendData:[[NSString stringWithFormat:@"--%@\r\n", boundary] dataUsingEncoding:NSUTF8StringEncoding]];
    [body appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"%@\"\r\n\r\n", param] dataUsingEncoding:NSUTF8StringEncoding]];
    [body appendData:[[NSString stringWithFormat:@"%@\r\n", [_params objectForKey:param]] dataUsingEncoding:NSUTF8StringEncoding]];
}

// add image data
NSData *imageData = UIImageJPEGRepresentation(imageToPost, 1.0);
if (imageData) {
    [body appendData:[[NSString stringWithFormat:@"--%@\r\n", boundary] dataUsingEncoding:NSUTF8StringEncoding]];
    [body appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"%@\"; filename=\"image.jpg\"\r\n", FileParamConstant] dataUsingEncoding:NSUTF8StringEncoding]];
    [body appendData:[[NSString stringWithString:@"Content-Type: image/jpeg\r\n\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
    [body appendData:imageData];
    [body appendData:[[NSString stringWithFormat:@"\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
}

[body appendData:[[NSString stringWithFormat:@"--%@--\r\n", boundary] dataUsingEncoding:NSUTF8StringEncoding]];

// setting the body of the post to the reqeust
[request setHTTPBody:body];

// set URL
[request setURL:requestURL];

Answer 2

我希望这段代码可以帮助其他人......

//create request
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init];

//Set Params
[request setHTTPShouldHandleCookies:NO];
[request setTimeoutInterval:60];
[request setHTTPMethod:@"POST"];

//Create boundary, it can be anything
NSString *boundary = @"------VohpleBoundary4QuqLuM1cE5lMwCy";

// set Content-Type in HTTP header
NSString *contentType = [NSString stringWithFormat:@"multipart/form-data; boundary=%@", boundary];
[request setValue:contentType forHTTPHeaderField: @"Content-Type"];

// post body
NSMutableData *body = [NSMutableData data];

//Populate a dictionary with all the regular values you would like to send.
NSMutableDictionary *parameters = [[NSMutableDictionary alloc] init];

[parameters setValue:param1 forKey:@"param1-name"];

[parameters setValue:param2 forKey:@"param2-name"];

[parameters setValue:param3 forKey:@"param3-name"];


// add params (all params are strings)
for (NSString *param in parameters) {
    [body appendData:[[NSString stringWithFormat:@"--%@\r\n", boundary] dataUsingEncoding:NSUTF8StringEncoding]];
    [body appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"%@\"\r\n\r\n", param] dataUsingEncoding:NSUTF8StringEncoding]];
    [body appendData:[[NSString stringWithFormat:@"%@\r\n", [parameters objectForKey:param]] dataUsingEncoding:NSUTF8StringEncoding]];
}

NSString *FileParamConstant = @"imageParamName";

NSData *imageData = UIImageJPEGRepresentation(imageObject, 1);

//Assuming data is not nil we add this to the multipart form
if (imageData)
{
    [body appendData:[[NSString stringWithFormat:@"--%@\r\n", boundary] dataUsingEncoding:NSUTF8StringEncoding]];
    [body appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"%@\"; filename=\"image.jpg\"\r\n", FileParamConstant] dataUsingEncoding:NSUTF8StringEncoding]];
    [body appendData:[@"Content-Type:image/jpeg\r\n\r\n" dataUsingEncoding:NSUTF8StringEncoding]];
    [body appendData:imageData];
    [body appendData:[[NSString stringWithFormat:@"\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
}

//Close off the request with the boundary
[body appendData:[[NSString stringWithFormat:@"--%@--\r\n", boundary] dataUsingEncoding:NSUTF8StringEncoding]];

// setting the body of the post to the request
[request setHTTPBody:body];

// set URL
[request setURL:[NSURL URLWithString:baseUrl]];

[NSURLConnection sendAsynchronousRequest:request
                                   queue:[NSOperationQueue mainQueue]
                       completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {

                           NSHTTPURLResponse* httpResponse = (NSHTTPURLResponse*)response;

                           if ([httpResponse statusCode] == 200) {

                               NSLog(@"success");
                           }

                       }];

Answer 3

看看Apple的SimpleURLConnections示例项目.您可以从那里使用PostController进行一些修改.

然而 - 这并不简单.上述解决方案的不同之处在于Apple正在使用流将文件流式传输到服务器.这比在上传期间保持编码图像数据更加便于记忆.它也更复杂.