iphone - 从 iPhone 将图像上传到 Rails 服务器(使用 Dragonfly)

Question

我正在尝试将图像从 iPhone 上传到 Rails，该图像配置为 Dragonfly gem.问题是我不断收到此错误:

Dragonfly::TempObject must be initialized with a String, a File, a Tempfile, another TempObject, or something that responds to .tempfile

我想知道这是否与从iPhone或其他设备发送的MIME类型有关。从浏览器上传工作正常。我希望能得到任何关于在哪里寻找问题根源的指导——iPhone还是服务器。

谢谢。

Answer 1

所以我也遇到过这个问题，但是这是从 iPhone 上传到 Rails 站点的方式。至于他们使用的 gem 可能存在问题，但是下面的代码肯定可以与 Rails 配合使用，因为我也必须学习如何将图像上传到 Rails。这是代码

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

NSString *boundary = @"------WebKitFormBoundary4QuqLuM1cE5lMwCy";
// 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];

NSMutableDictionary *parameters = [[NSMutableDictionary alloc] initWithCapacity:11];
[parameters setValue:@”information” forKey:@"Information"];

然后继续将所有参数添加到您需要随请求发送的字典中。

// 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]];
}


//Compress the data
NSString *FileParamConstant = @"image";
// add image data
CGFloat compression = 0.9f;
CGFloat maxCompression = 0.1f;
int maxFileSize = 250*1024;

NSData *imageData = [[NSData alloc] initWithContentsOfFile:imagePath];

while ([imageData length] > maxFileSize && compression > maxCompression)
{
    compression -= 0.1;
    imageData = UIImageJPEGRepresentation([UIImage imageNamed:imagePath], compression);
}
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:[NSURL URLWithString:[[URLLibrary sharedInstance] getCreateFeedURL]]];
NSURLResponse* response;
NSError* error;

[NSURLConnection sendAsynchronousRequest:request 
                                   queue:[NSOperationQueue mainQueue]
                       completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {
                           make gui changes saying things worked
                       }];

请注意，由于网络浏览器的工作方式，图像需要临时写入文件系统。这就是从 iPhone 将图像上传到 Rails 站点的方法。