iOS开发-文件上传原理

//
//  UploadFile.h
//  02.Post上传
//
//  Created by wyh on 15-1-29.
//  Copyright (c) 2015年 itcast. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface UploadFile : NSObject

- (void)uploadFileWithURL:(NSURL *)url data:(NSData *)data;

@end

//
//  UploadFile.m
//  02.Post上传
//
//  Created by why on 15-1-29.
//  Copyright (c) 2015年 itcast. All rights reserved.
//

#import "UploadFile.h"

@implementation UploadFile
// 拼接字符串
static NSString *boundaryStr = @"--";   // 分隔字符串
static NSString *randomIDStr;           // 本次上传标示字符串
static NSString *uploadID;              // 上传(php)脚本中，接收文件字段

- (instancetype)init
{
    self = [super init];
    if (self) {
        randomIDStr = @"itcast";
        uploadID = @"uploadFile";
    }
    return self;
}

#pragma mark - 私有方法
- (NSString *)topStringWithMimeType:(NSString *)mimeType uploadFile:(NSString *)uploadFile
{
    NSMutableString *strM = [NSMutableString string];

    [strM appendFormat:@"%@%@\n", boundaryStr, randomIDStr];
    [strM appendFormat:@"Content-Disposition: form-data; name=\"%@\"; filename=\"%@\"\n", uploadID, uploadFile];
    [strM appendFormat:@"Content-Type: %@\n\n", mimeType];

    NSLog(@"%@", strM);
    return [strM copy];
}

- (NSString *)bottomString
{
    NSMutableString *strM = [NSMutableString string];

    [strM appendFormat:@"%@%@\n", boundaryStr, randomIDStr];
    [strM appendString:@"Content-Disposition: form-data; name=\"submit\"\n\n"];
    [strM appendString:@"Submit\n"];
    [strM appendFormat:@"%@%@--\n", boundaryStr, randomIDStr];

    NSLog(@"%@", strM);
    return [strM copy];
}

#pragma mark - 上传文件
- (void)uploadFileWithURL:(NSURL *)url data:(NSData *)data
{
    // 1> 数据体
    NSString *topStr = [self topStringWithMimeType:@"image/png" uploadFile:@"头像1.png"];
    NSString *bottomStr = [self bottomString];

    NSMutableData *dataM = [NSMutableData data];
    [dataM appendData:[topStr dataUsingEncoding:NSUTF8StringEncoding]];
    [dataM appendData:data];
    [dataM appendData:[bottomStr dataUsingEncoding:NSUTF8StringEncoding]];

    // 1. Request
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url cachePolicy:0 timeoutInterval:2.0f];

    // dataM出了作用域就会被释放,因此不用copy
    request.HTTPBody = dataM;

    // 2> 设置Request的头属性
    request.HTTPMethod = @"POST";

    // 3> 设置Content-Length
    NSString *strLength = [NSString stringWithFormat:@"%ld", (long)dataM.length];
    [request setValue:strLength forHTTPHeaderField:@"Content-Length"];

    // 4> 设置Content-Type
    NSString *strContentType = [NSString stringWithFormat:@"multipart/form-data; boundary=%@", randomIDStr];
    [request setValue:strContentType forHTTPHeaderField:@"Content-Type"];

    // 3> 连接服务器发送请求
    [NSURLConnection sendAsynchronousRequest:request queue:[[NSOperationQueue alloc] init] completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) {

        NSString *result = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
        NSLog(@"%@", result);
    }];
}

@end

//
//  MJViewController.m
//  02.Post上传
//
//  Created by wyh on 15-1-29.
//  Copyright (c) 2015年 itcast. All rights reserved.
//

#import "ViewController.h"
#import "UploadFile.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];

    UploadFile *upload = [[UploadFile alloc] init];

    NSString *urlString = @"http://localhost/upload.php";

    NSString *path = [[NSBundle mainBundle] pathForResource:@"头像1.png" ofType:nil];
    NSData *data = [NSData dataWithContentsOfFile:path];

    [upload uploadFileWithURL:[NSURL URLWithString:urlString] data:data];
}

@end