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  • ios 文件上传, post数据

    转自:http://www.maxiaoguo.com/clothes/267.html

    一、文件下载

    获取资源文件大小有两张方式

    1、

    HTTP HEAD方法
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url cachePolicy:0 timeoutInterval:kTimeout];
    request.HTTPMethod = @"HEAD";
    [NSURLConnection sendAsynchronousRequest:request queue:self.myQueue completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) {
        NSLog(@"%@", response);
        NSLog(@"---------------");
        NSLog(@"%@", data);
    }];
    执行測试代码能够发现。HEAD方法仅仅是返回资源信息,而不会返回数据体
    应用场景:
    获取资源Mimetype
    获取资源文件大小。用于端点续传或多线程下载
    2

    使用块代码获取网络资源大小的方法
    - (void)fileSizeWithURL:(NSURL *)url completion:(void (^)(long long contentLength))completion
    {
        NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url cachePolicy:0 timeoutInterval:kTimeout];
        request.HTTPMethod = @"HEAD"; 
        NSURLResponse *response = nil;
        [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:NULL];
        
        completion(response.expectedContentLength);
    }

    确定每次下载数据包的伪代码实现

    - (void)downloadFileWithURL:(NSURL *)url
    {
        [self fileSizeWithURL:url completion:^(long long contentLength) {
            NSLog(@"文件总大小:%lld", contentLength);        
            // 依据大小下载文件
                   while (contentLength > kDownloadBytes) {
                NSLog(@"每次下载长度:%lld", (long long)kDownloadBytes);
                contentLength -= kDownloadBytes;
            }
            NSLog(@"最后下载字节数:%lld", contentLength);
        }];
    }

    HTTP Range的演示样例
    通过设置Range能够指定每次从网路下载数据包的大小
    Range演示样例
    bytes=0-499 从0到499的头500个字节
    bytes=500-999 从500到999的第二个500字节
    bytes=500- 从500字节以后的全部字节
    bytes=-500 最后500个字节
    bytes=500-599,800-899 同一时候指定几个范围
    Range小结
    - 用于分隔
    前面的数字表示起始字节数
    后面的数组表示截止字节数,没有表示到末尾
    , 用于分组,能够一次指定多个Range。只是非常少用

    分段Range代码实现
    long long fromBytes = 0;
    long long toBytes = 0;
    while (contentLength > kDownloadBytes) {
        toBytes = fromBytes + kDownloadBytes - 1;
        NSString *range = [NSString stringWithFormat:@"bytes=%lld-%lld", fromBytes, toBytes];
        NSLog(@"range %@", range);
        fromBytes += kDownloadBytes;
        contentLength -= kDownloadBytes;
    }
    fromBytes = fromBytes + contentLength - 1;
    NSString *range = [NSString stringWithFormat:@"bytes=%lld-%lld", fromBytes, toBytes];
    NSLog(@"range %@", range);
    

    分段下载文件
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url cachePolicy:NSURLRequestReloadIgnoringCacheData timeoutInterval:kTimeout];
    NSString *range = [NSString stringWithFormat:@"bytes=%lld-%lld", from, end];
    [request setValue:range forHTTPHeaderField:@"Range"];
    
    NSURLResponse *response = nil;
    NSData *data = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:NULL];
        
    NSLog(@"%@-%@-%ld", range, response, (unsigned long)data.length);
    提示:
    假设GET包括Range请求头。响应会以状态码206(PartialContent)返回而不是200(OK)

    将数据写入文件
    // 打开缓存文件
    NSFileHandle *fp = [NSFileHandle fileHandleForWritingAtPath:self.cachePath];
    // 假设文件不存在。直接写入数据
    if (!fp) {
        [data writeToFile:self.cachePath atomically:YES];
    } else {
        // 移动到文件末尾
        [fp seekToEndOfFile];
        // 将数据文件追加到文件末尾
        [fp writeData:data];
        // 关闭文件句柄
        [fp closeFile];
    }

    检查文件大小
    // 推断文件是否存在
    if ([[NSFileManager defaultManager] fileExistsAtPath:self.cachePath]) {
        NSDictionary *dict = [[NSFileManager defaultManager] attributesOfItemAtPath:self.cachePath error:NULL];
        return [dict[NSFileSize] longLongValue];
    } else {
        return 0;
    }
    
    提示:因为数据是追加的。为了避免反复从网络下载文件,在下载之前
    推断缓存路径中文件是否已经存在
    假设存在检查文件大小
    假设文件大小与网络资源大小一致。则不再下载

    所有代码例如以下

    //
    //  MJViewController.m
    //  01.文件下载
    //
    //  Created by apple on 14-4-29.
    //  Copyright (c) 2014年 itcast. All rights reserved.
    //
    
    #import "MJViewController.h"
    #import "FileDownload.h"
    
    @interface MJViewController ()
    @property (nonatomic, strong) FileDownload *download;
    @property (weak, nonatomic) IBOutlet UIImageView *imageView;
    @end
    
    @implementation MJViewController
    
    - (void)viewDidLoad
    {
        [super viewDidLoad];
        
        self.download = [[FileDownload alloc] init];
        [self.download downloadFileWithURL:[NSURL URLWithString:@"http://localhost/itcast/images/head4.png"] completion:^(UIImage *image) {
            
            self.imageView.image = image;
        }];
    }
    
    @end

    //
    //  FileDownload.m
    //  01.文件下载
    //
    //  Created by apple on 14-4-29.
    //  Copyright (c) 2014年 itcast. All rights reserved.
    //
    
    #import "FileDownload.h"
    #import "NSString+Password.h"
    
    #define kTimeOut        2.0f
    // 每次下载的字节数
    #define kBytesPerTimes  20250
    
    @interface FileDownload()
    @property (nonatomic, strong) NSString *cacheFile;
    @property (nonatomic, strong) UIImage *cacheImage;
    @end
    
    @implementation FileDownload
    /**
     为了保证开发的简单,全部方法都不使用多线程,全部的注意力都保持在文件下载上
     
     在开发中假设碰到比較绕的计算问题时,建议:
     1> 測试数据不要太大
     2> 測试数据的数值变化,可以用笔算计算出准确的数值
     3> 编写代码对比測试
    
     */
    //- (NSString *)cacheFile
    //{
    //    if (!_cacheFile) {
    //        NSString *cacheDir = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES)[0];
    //        _cacheFile = [cacheDir stringByAppendingPathComponent:@"123.png"];
    //    }
    //    return _cacheFile;
    //}
    - (UIImage *)cacheImage
    {
        if (!_cacheImage) {
            _cacheImage = [UIImage imageWithContentsOfFile:self.cacheFile];
        }
        return _cacheImage;
    }
    
    - (void)setCacheFile:(NSString *)urlStr
    {
        NSString *cacheDir = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES)[0];
        urlStr = [urlStr MD5];
        
        _cacheFile = [cacheDir stringByAppendingPathComponent:urlStr];
    }
    
    - (void)downloadFileWithURL:(NSURL *)url completion:(void (^)(UIImage *image))completion
    {
        // GCD中的串行队列异步方法
        dispatch_queue_t q = dispatch_queue_create("cn.itcast.download", DISPATCH_QUEUE_SERIAL);
        
        dispatch_async(q, ^{
            NSLog(@"%@", [NSThread currentThread]);
            
            // 把对URL进行MD5加密之后的结果当成文件名称
            self.cacheFile = [url absoluteString];
            
            // 1. 从网络下载文件,须要知道这个文件的大小
            long long fileSize = [self fileSizeWithURL:url];
            // 计算本地缓存文件大小
            long long cacheFileSize = [self localFileSize];
            
            if (cacheFileSize == fileSize) {
                dispatch_async(dispatch_get_main_queue(), ^{
                    completion(self.cacheImage);
                });
                NSLog(@"文件已经存在");
                return;
            }
            
            // 2. 确定每一个数据包的大小
            long long fromB = 0;
            long long toB = 0;
            // 计算起始和结束的字节数
            while (fileSize > kBytesPerTimes) {
                // 20480 + 20480
                //
                toB = fromB + kBytesPerTimes - 1;
                
                // 3. 分段下载文件
                [self downloadDataWithURL:url fromB:fromB toB:toB];
                
                fileSize -= kBytesPerTimes;
                fromB += kBytesPerTimes;
            }
            [self downloadDataWithURL:url fromB:fromB toB:fromB + fileSize - 1];
    
            dispatch_async(dispatch_get_main_queue(), ^{
                completion(self.cacheImage);
            });        
        });
    }
    
    #pragma mark 下载指定字节范围的数据包
    /**
     NSURLRequestUseProtocolCachePolicy = 0,        // 默认的缓存策略,内存缓存
     
     NSURLRequestReloadIgnoringLocalCacheData = 1,  // 忽略本地的内存缓存
     NSURLRequestReloadIgnoringCacheData
     */
    - (void)downloadDataWithURL:(NSURL *)url fromB:(long long)fromB toB:(long long)toB
    {
        NSLog(@"数据包:%@", [NSThread currentThread]);
        
        NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url cachePolicy:NSURLRequestReloadIgnoringCacheData timeoutInterval:kTimeOut];
        
        // 指定请求中所要GET的字节范围
        NSString *range = [NSString stringWithFormat:@"Bytes=%lld-%lld", fromB, toB];
        [request setValue:range forHTTPHeaderField:@"Range"];
        NSLog(@"%@", range);
        
        NSURLResponse *response = nil;
        NSData *data = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:NULL];
        
        // 写入文件,覆盖文件不会追加
    //    [data writeToFile:@"/Users/aplle/Desktop/1.png" atomically:YES];
        [self appendData:data];
        
        NSLog(@"%@", response);
    }
    
    #pragma mark - 读取本地缓存文件大小
    - (long long)localFileSize
    {
        // 读取本地文件信息
        NSDictionary *dict = [[NSFileManager defaultManager] attributesOfItemAtPath:self.cacheFile error:NULL];
        NSLog(@"%lld", [dict[NSFileSize] longLongValue]);
        
        return [dict[NSFileSize] longLongValue];
    }
    
    #pragma mark - 追加数据到文件
    - (void)appendData:(NSData *)data
    {
        // 推断文件是否存在
        NSFileHandle *fp = [NSFileHandle fileHandleForWritingAtPath:self.cacheFile];
        // 假设文件不存在创建文件
        if (!fp) {
            [data writeToFile:self.cacheFile atomically:YES];
        } else {
            // 假设文件已经存在追加文件
            // 1> 移动到文件末尾
            [fp seekToEndOfFile];
            // 2> 追加数据
            [fp writeData:data];
            // 3> 写入文件
            [fp closeFile];
        }
    }
    
    #pragma mark - 获取网络文件大小
    - (long long)fileSizeWithURL:(NSURL *)url
    {
        // 默认是GET
        NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url cachePolicy:0 timeoutInterval:kTimeOut];
        
        // HEAD 头,仅仅是返回文件资源的信息,不返回详细是数据
        // 假设要获取资源的MIMEType,也必须用HEAD,否则,数据会被反复下载两次
        request.HTTPMethod = @"HEAD";
    
        // 使用同步方法获取文件大小
        NSURLResponse *response = nil;
        
        [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:NULL];
        
        // expectedContentLength文件在网络上的大小
        NSLog(@"%lld", response.expectedContentLength);
        
        return response.expectedContentLength;
    }
    
    @end
    


    二、文件上传

    代码例如以下

    //
    //  MJViewController.m
    //  02.Post上传
    //
    //  Created by apple on 14-4-29.
    //  Copyright (c) 2014年 itcast. All rights reserved.
    //
    
    #import "MJViewController.h"
    #import "UploadFile.h"
    
    @interface MJViewController ()
    
    @end
    
    @implementation MJViewController
    
    - (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
    

    //
    //  UploadFile.m
    //  02.Post上传
    //
    //  Created by apple on 14-4-29.
    //  Copyright (c) 2014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:@"%@%@
    ", boundaryStr, randomIDStr];
        [strM appendFormat:@"Content-Disposition: form-data; name="%@"; filename="%@"
    ", uploadID, uploadFile];
        [strM appendFormat:@"Content-Type: %@
    
    ", mimeType];
        
        NSLog(@"%@", strM);
        return [strM copy];
    }
    
    - (NSString *)bottomString
    {
        NSMutableString *strM = [NSMutableString string];
        
        [strM appendFormat:@"%@%@
    ", boundaryStr, randomIDStr];
        [strM appendString:@"Content-Disposition: form-data; name="submit"
    
    "];
        [strM appendString:@"Submit
    "];
        [strM appendFormat:@"%@%@--
    ", 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server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
    



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  • 原文地址:https://www.cnblogs.com/claireyuancy/p/6923683.html
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