简单网络请求封装

//
//  HTTPRequset.h
//  请求类分装
//
//  Created by qianfeng on 15-7-26.
//  Copyright (c) 2015年 qq. All rights reserved.
//
//通过代理和block实现函数回调,可选其一
#import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>
@class HTTPRequset;
@protocol HTTPRequsetDelegate <NSObject>

@optional
/**
    进度的回调
 */
- (void)requestDidProgress:(CGFloat)progress;
//请求完成的回调
- (void)requestDidfinish:(HTTPRequset *)httprequest;
/**
    请求完成的回调
 */
- (void)requestDidError:(NSError *)error;
@end

/**
    请求类
 */
@interface HTTPRequset : NSObject
/**
    网络请求返回数据源
 */
@property(nonatomic,strong) NSData * responseData;
/**
    字符串形式
 */
@property(nonatomic,copy ) NSString * reponseString;
/**
    代理
 */
@property(nonatomic,assign)id<HTTPRequsetDelegate>delegate;
/**
 使用block实现回调下载进程
 */
@property(nonatomic,copy) void(^requestDidProgressBlock)(CGFloat progress);
/**
 使用block实现回调对象
 */
@property(nonatomic,copy) void(^requestDidFinishBlock)(HTTPRequset * request);
/**
 使用block实现回调错误信息
 */
@property(nonatomic,copy) void(^requestDidErrorBlock)(NSError * error);

/**
 构造方法
 */
- (id)initWithUrl:(NSURL *)url;
/**
    开始网络请求
 */
- (void)startRequest;
@end

//
//  HTTPRequset.m
//  请求类分装
//
//  Created by qianfeng on 15-7-26.
//  Copyright (c) 2015年 qq. All rights reserved.
//

#import "HTTPRequset.h"

@interface HTTPRequset ()<NSURLConnectionDataDelegate,NSURLConnectionDelegate>
{
    NSURL * _url;
    //保存下载数据
    NSMutableData * _downloadData;

    //总大小
    long long _fileSizeBytes;
}
@end

@implementation HTTPRequset
- (id)initWithUrl:(NSURL *)url
{
    self = [super init];
    if (self) {

        _url = url;
        _downloadData = [NSMutableData data];
    }
    return self;
}
- (void)startRequest
{
    NSURLRequest * request = [NSURLRequest requestWithURL:_url];
    [NSURLConnection connectionWithRequest:request delegate:self];
}
#pragma mark - 代理方法
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
    //清空数据
    _downloadData.length = 0;
    //获取文件总大小
    _fileSizeBytes = [response expectedContentLength];
}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
    //追加
    [_downloadData appendData:data];
    //计算进度
    float progress = (float) _downloadData.length / _fileSizeBytes;
    if ([self.delegate respondsToSelector:@selector(requestDidProgress:)]) {
        [self.delegate requestDidProgress:progress];
    }
    self.requestDidProgressBlock(progress);

}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
    //请求取消
    [connection cancel];

    //
    _responseData = _downloadData;
    _reponseString = [[NSString alloc]initWithData:_downloadData encoding:NSUTF8StringEncoding];
    self.requestDidFinishBlock(self);
    if ([self.delegate respondsToSelector:@selector(requestDidfinish:)]) {
        [self.delegate requestDidfinish:self];
    }

}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
    //请求取消
    [connection cancel];
    self.requestDidErrorBlock(error);
    if ([self.delegate respondsToSelector:@selector(requestDidError:)]) {
        [self.delegate requestDidError:error];
    }

}

@end