ios 文件上传， post数据

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ios 文件上传， post数据

分类： ios

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、

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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);

}];

运行测试代码可以发现，HEAD方法只是返回资源信息，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

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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

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- (void)downloadFileWithURL:(NSURL *)url

{

[self fileSizeWithURL:url completion:^(long long contentLength) {

NSLog(@"文件总大小：%lld", contentLength);

// 根据大小下载文件

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的示例

通过设置Range可以指定每次从网路下载数据包的大小

Range示例

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字节以后的所有字节

bytes=-500 最后500个字节

bytes=500-599,800-899 同时指定几个范围

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，可以一次指定多个Range，不过很少用

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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);

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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：

如果GET包含Range请求头，响应会以状态码206（PartialContent）返回而不是200（OK）

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将数据写入文件

// 打开缓存文件

NSFileHandle *fp = [NSFileHandle fileHandleForWritingAtPath:self.cachePath];

// 如果文件不存在，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];

}

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检查文件大小

// 判断文件是否存在

if ([[NSFileManager defaultManager] fileExistsAtPath:self.cachePath]) {

NSDictionary *dict = [[NSFileManager defaultManager] attributesOfItemAtPath:self.cachePath error:NULL];

return [dict[NSFileSize] longLongValue];

} else {

return 0;

}

提示：由于数据是追加的，为了避免重复从网络下载文件，在下载之前

判断缓存路径中文件是否已经存在

如果存在检查文件大小

如果文件大小与网络资源大小一致，则不再下载

全部代码如下

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//

// 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

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//

// 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,所有方法都不使用多线程,所有的注意力都保持在文件下载上

在开发中如果碰到比较绕的计算问题时,建议:

1> 测试数据不要太大

2> 测试数据的数值变化,能够用笔算计算出准确的数值

3> 编写代码对照测试

*/

//- (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

self.cacheFile = [url absoluteString];

// 1. 从网络下载文件,需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

{

// 判断文件是否存在

NSFileHandle *fp = [NSFileHandle fileHandleForWritingAtPath:self.cacheFile];

// 如果文件不存在创建文件

if (!fp) {

[data writeToFile:self.cacheFile atomically:YES];

} else {

// 如果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,只是返回文件资源的信息,不返回具体是数据

// 如果要获取资源的MIMEType,也必须用HEAD,否则,数据会被重复下载两次

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

代码如下

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//

// 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

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//

// 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:@"%@%@\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

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