HTTP发布脚本不添加参数

Question

我有以下脚本写在Objective-C中。代码从SO上的问题修改（问题是here和here）。照片上传到服务器，但参数未正确添加。继承人的代码：

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

NSString *boundary = @"---------------------------14737809831466499882746641449"; 

// 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]; 

// Dictionary that holds post parameters. 
NSMutableDictionary* _params = [[NSMutableDictionary alloc] init]; 
[_params setObject:Name forKey:@"username"]; 

// the boundary string 
NSString *BoundaryConstant = @"----------V2ymHFg03ehbqgZCaKO6jy"; 

// string constant for the post parameter 
NSString* FileParamConstant = @"FILE1"; 

// the server url to which the image 
NSURL* requestURL = [NSURL URLWithString:uploadURLString]; 

// add params (all params are strings) 
for (NSString *param in _params) { 
    [body appendData:[[NSString stringWithFormat:@"--%@\r\n", BoundaryConstant] dataUsingEncoding:NSUTF8StringEncoding]]; 
    [body appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; charset:UTF-8; name=\"%@\"\r\n\r\n", param] dataUsingEncoding:NSUTF8StringEncoding]]; 
    [body appendData:[[NSString stringWithFormat:@"%@\r\n", [_params objectForKey:param]] dataUsingEncoding:NSUTF8StringEncoding]]; 
} 

// add image data 
UIImage *newImage = self.urlImageOfUser.image; 
NSData *imageData = UIImageJPEGRepresentation(newImage, 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:[@"Content-Type: image/png\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 request 
[request setHTTPBody:body]; 

// set the content-length 
NSString *postLength = [NSString stringWithFormat:@"%d", [body length]]; 
[request setValue:postLength forHTTPHeaderField:@"Content-Length"]; 

// set URL 
[request setURL:requestURL]; 

NSData *returnData = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil]; 
NSString *returnString = [[NSString alloc] initWithData:returnData encoding:NSUTF8StringEncoding]; 

NSLog(@"%@", returnString); 

该最终NSLog表明添加的参数（用户名）完全是空的。有什么我失踪？

Answer 1

我得到它的工作，这是我用的新代码：

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]]; 
} 

我认为，唯一的区别是charset参数。

Answer 2

我的建议：

NSString *stringBody = @""; 
NSArray *allKeys = parameters.allKeys; 
NSArray *allValues = parameters.allValues; 

for (int i = 0; i < allKeys.count; i++) { 
    NSString *key = allKeys[i]; 
    NSString *value = allValues[i]; 
    stringBody = [stringBody stringByAppendingString:[NSString stringWithFormat:@"%@=%@&", key, value]]; 
} 

完整代码：

FOUNDATION_EXPORT NSString *GetWebServiceResponseHTTP_POST(NSString *url, NSString *webServiceName, NSMutableDictionary *parameters) { 
    NSString *stringBody = @""; 
    NSArray *allKeys = parameters.allKeys; 
    NSArray *allValues = parameters.allValues; 

    for (int i = 0; i < allKeys.count; i++) { 
     NSString *key = allKeys[i]; 
     NSString *value = allValues[i]; 
     stringBody = [stringBody stringByAppendingString:[NSString stringWithFormat:@"%@=%@&", key, value]]; 
    } 

    NSURL *completeURL = [NSURL URLWithString:[NSString stringWithFormat:@"%@/%@", url, webServiceName]]; 
    NSData *body = [stringBody dataUsingEncoding:NSUTF8StringEncoding]; 
    NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:completeURL]; 
    [request setHTTPMethod:@"POST"]; 
    [request setValue:@"some value" forHTTPHeaderField:@"some header"]; 
    [request setHTTPBody:body]; 
    [request setValue:[NSString stringWithFormat:@"%d", body.length] forHTTPHeaderField:@"Content-Length"]; 
    [request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"]; 

    NSError *error = [[NSError alloc] init]; 
    NSHTTPURLResponse *responseCode = nil; 
    NSData *responseData = [NSURLConnection sendSynchronousRequest:request returningResponse:&responseCode error:&error]; 

    if (responseCode.statusCode != 200) { 
     NSLog(@"Error getting %@, HTTP status code %i", url, responseCode.statusCode); 
     return nil; 
    } 

    NSString *responseString = [[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding];  
    return responseString; 
}