從Cocoa發送POST請求到Tumblr

Question

此代碼段不起作用，我得到「身份驗證失敗」。來自服務器的響應。有任何想法嗎？

NSMutableURLRequest *request = [[NSMutableURLRequest alloc] 
            initWithURL: 
            [NSURL URLWithString:@"http://www.tumblr.com/api/write"]]; 
    [request setHTTPMethod:@"POST"]; 
    [request addValue:_tumblrLogin forHTTPHeaderField:@"email"]; 
    [request addValue:_tumblrPassword forHTTPHeaderField:@"password"]; 
    [request addValue:@"regular" forHTTPHeaderField:@"type"]; 
    [request addValue:@"theTitle" forHTTPHeaderField:@"title"]; 
    [request addValue:@"theBody" forHTTPHeaderField:@"body"]; 

    NSLog(@"Tumblr Login:%@\nTumblr Password:%@", _tumblrLogin, _tumblrPassword); 

    [NSURLConnection connectionWithRequest:request delegate:self]; 

    [request release]; 

兩個_tumblrLogin和_tumblrPassword通過stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding其他地方在我的代碼運行。我的登錄電子郵件格式爲「address+test@test.com」。它可以直接登錄到tumblr，但是我想知道「+」字符是否會導致編碼問題？它沒有被轉義。它應該是？

---

由於馬丁的建議，我現在使用CFURLCreateStringByAddingPercentEscapes逃脫我的登錄名和密碼。我仍然有同樣的問題，但是，我的身份驗證失敗。

Answer 1

問題是您沒有創建正確的HTTP POST請求。 POST請求需要格式正確的多部分MIME編碼主體，其中包含要發送到服務器的所有參數。您正在嘗試將參數設置爲根本不起作用的HTTP標頭。

該代碼會做你想要什麼，尤其要注意NSString類別創建一個有效的多部分MIME字符串：

@interface NSString (MIMEAdditions) 
+ (NSString*)MIMEBoundary; 
+ (NSString*)multipartMIMEStringWithDictionary:(NSDictionary*)dict; 
@end 

@implementation NSString (MIMEAdditions) 
//this returns a unique boundary which is used in constructing the multipart MIME body of the POST request 
+ (NSString*)MIMEBoundary 
{ 
    static NSString* MIMEBoundary = nil; 
    if(!MIMEBoundary) 
     MIMEBoundary = [[NSString alloc] initWithFormat:@"----_=_YourAppNameNoSpaces_%@_=_----",[[NSProcessInfo processInfo] globallyUniqueString]]; 
    return MIMEBoundary; 
} 
//this create a correctly structured multipart MIME body for the POST request from a dictionary 
+ (NSString*)multipartMIMEStringWithDictionary:(NSDictionary*)dict 
{ 
    NSMutableString* result = [NSMutableString string]; 
    for (NSString* key in dict) 
    { 
     [result appendFormat:@"--%@\r\nContent-Disposition: form-data; name=\"%@\"\r\n\r\n%@\r\n",[NSString MIMEBoundary],key,[dict objectForKey:key]]; 
    } 
    [result appendFormat:@"\r\n--%@--\r\n",[NSString MIMEBoundary]]; 
    return result; 
} 
@end 


@implementation YourObject 
- (void)postToTumblr 
{ 
    NSMutableURLRequest *request = [[NSMutableURLRequest alloc] 
            initWithURL: 
            [NSURL URLWithString:@"http://www.tumblr.com/api/write"]]; 
    [request setHTTPMethod:@"POST"]; 
    //tell the server to expect 8-bit encoded content as we're sending UTF-8 data, 
    //and UTF-8 is an 8-bit encoding 
    [request addValue:@"8bit" forHTTPHeaderField:@"Content-Transfer-Encoding"]; 
    //set the content-type header to multipart MIME 
    [request addValue: [NSString stringWithFormat:@"multipart/form-data; boundary=%@",[NSString MIMEBoundary]] forHTTPHeaderField: @"Content-Type"]; 

    //create a dictionary for all the fields you want to send in the POST request 
    NSDictionary* postData = [NSDictionary dictionaryWithObjectsAndKeys: 
           _tumblrLogin, @"email", 
           _tumblrPassword, @"password", 
           @"regular", @"type", 
           @"theTitle", @"title", 
           @"theBody", @"body", 
           nil]; 
    //set the body of the POST request to the multipart MIME encoded dictionary 
    [request setHTTPBody: [[NSString multipartMIMEStringWithDictionary: postData] dataUsingEncoding: NSUTF8StringEncoding]]; 
    NSLog(@"Tumblr Login:%@\nTumblr Password:%@", _tumblrLogin, _tumblrPassword); 
    [NSURLConnection connectionWithRequest:request delegate:self]; 
    [request release]; 
} 
@end 

Answer 2

根據對this question的回答，stringByAddingPercentEscapesUsingEncoding:不會執行完整的轉義編碼。無論出於何種原因，這種方法的CoreFoundation版本確實，但是：

[(NSString *) CFURLCreateStringByAddingPercentEscapes(NULL, 
    (CFStringRef)[[self mutableCopy] autorelease], NULL, 
    CFSTR("=,!$&'()*+;@?\n\"<>#\t :/"), kCFStringEncodingUTF8) autorelease]; 

您還可以使用的NSMutableString的replaceOccurencesOfString:withString:options:方法做手工更換，但該方法是多重複和繁瑣。 （See here。）