post上传文件

- (BOOL)sendPhotoToTumblr:(NSString *)photo withCaption:(NSString *)caption;
{
        //get image data from file
        NSData *imageData = [NSData dataWithContentsOfFile:photo];       
        //stop on error
        if (!imageData) return NO;
       
        //Create dictionary of post arguments
        NSArray *keys = [[NSArray alloc] initWithObjects:@"email",@"password",@"type",@"caption",nil];
        NSArray *objects = [[NSArray alloc] initWithObjects:
                        [NSString stringWithFormat:@"%@",CFPreferencesCopyAppValue(CFSTR("TumblrEmail"), kCFPreferencesCurrentApplication)],
                        [NSString stringWithFormat:@"%@",CFPreferencesCopyAppValue(CFSTR("TumblrPassword"), kCFPreferencesCurrentApplication)],
                        @"photo", caption, nil];
        NSDictionary *keysDict = [[NSDictionary alloc] initWithObjects:objects forKeys:keys];
       
        //create tumblr photo post
        NSURLRequest *tumblrPost = [self createTumblrRequest:keysDict withData:imageData];
       
        //send request, return YES if successful
        tumblrConnection = [[NSURLConnection alloc] initWithRequest:tumblrPost delegate:self];
        if (!tumblrConnection) {
                NSLog(@"Failed to submit request");
                return NO;
        } else {
                NSLog(@"Request submitted");
                receivedData = [[NSMutableData data] retain];
                return YES;
        }
}

-(NSURLRequest *)createTumblrRequest:(NSDictionary *)postKeys withData:(NSData *)data
{
        //create the URL POST Request to tumblr
        NSURL *tumblrURL = [NSURL URLWithString:@"http://www.tumblr.com/api/write"];
        NSMutableURLRequest *tumblrPost = [NSMutableURLRequest requestWithURL:tumblrURL];
        [tumblrPost setHTTPMethod:@"POST"];
       
        //Add the header info
        NSString *stringBoundary = [NSString stringWithString:@"0xKhTmLbOuNdArY"];
        NSString *contentType = [NSString stringWithFormat:@"multipart/form-data; boundary=%@",stringBoundary];
        [tumblrPost addValue:contentType forHTTPHeaderField: @"Content-Type"];
       
        //create the body
        NSMutableData *postBody = [NSMutableData data];
        [postBody appendData:[[NSString stringWithFormat:@"--%@\r\n",stringBoundary] dataUsingEncoding:NSUTF8StringEncoding]];
       
        //add key values from the NSDictionary object
        NSEnumerator *keys = [postKeys keyEnumerator];
        int i;
        for (i = 0; i < [postKeys count]; i++) {
                NSString *tempKey = [keys nextObject];
                [postBody appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"%@\"\r\n\r\n",tempKey] dataUsingEncoding:NSUTF8StringEncoding]];
                [postBody appendData:[[NSString stringWithFormat:@"%@",[postKeys objectForKey:tempKey]] dataUsingEncoding:NSUTF8StringEncoding]];
                [postBody appendData:[[NSString stringWithFormat:@"\r\n--%@\r\n",stringBoundary] dataUsingEncoding:NSUTF8StringEncoding]];
        }

        //add data field and file data
        [postBody appendData:[[NSString stringWithString:@"Content-Disposition: form-data; name=\"data\"\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
        [postBody appendData:[[NSString stringWithString:@"Content-Type: application/octet-stream\r\n\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
        [postBody appendData:[NSData dataWithData:data]];
        [postBody appendData:[[NSString stringWithFormat:@"\r\n--%@--\r\n",stringBoundary] dataUsingEncoding:NSUTF8StringEncoding]];
       
        //add the body to the post
        [tumblrPost setHTTPBody:postBody];

        return tumblrPost;
}

1. 设置HttpWebRequest的Content-Type，一定boundary，这里是--ABCD

Content-Type:multipart/form-data;boundary=--ABCD  
2. post内容，各部分以--ABCD开头，结尾以--ABCD--结尾

--ABCD 
Content-Disposition: form-data; name="title" 
\r\n 
Today 
--ABCD 
Content-Disposition: form-data; name="1.txt"; filename="C:\1.txt" 
Content-Type: text/plain 
\r\n 
<这里是1.txt文件的内容> 
--ABCD--\r\n 

 

注意：换行的地方也是要加\r\n的