iOS网络请求之上传图片：从示例到源码解析 — 以上传Face++SDK回调的图片为例（HYNetworking，AFNetworking，XMNetworking）

前言

• 网络框架

本文一开始上传图片以调使用HYNetworking的API为例，这个网络框架是以AFNetworking为基础进行的封装。HYNetworking内部实现上传图片的时候，其实就是采使用AFNetworking关于上传图片的API，都是AFNetworking里面一个API。后面再讲XMNetworking上传图片请求的操作方法，它也是基于AFNetworking上传进行的封装，不过比HYNetworking更加隐晦而已。

• 需求背景

这里的需求背景是，我们的app采使用全球领先的AI方案提供商 — 旷视科技 的Face++ SDK进行身份证识别：它识别到身份证后会回调一个图片数据，我们使用此图片向Face++公司的服务器请求验证，该请求通过则block回调成功，接着将图片数据保存到手机本地，而后在合适的时机（比方，点击“完成”或者者“下一步”按钮）把图片数据上传到自己公司的服务器。

• 先上总结

上传图片的流程图如下所示

上传图片流程图

1. 获取回调图片

下面举例一个典型Face++的例子

• 点击“扫描身份证按钮”事件解决

// 身份证扫描正面__weak typeof(self) weakSelf = self;BOOL idcard = [MGIDCardManager getLicense];if (!idcard) {    [[[UIAlertView alloc] initWithTitle:@"提醒" message:@"SDK受权失败，请检查" delegate:self cancelButtonTitle:@"完成" otherButtonTitles:nil, nil] show];    return;}if ([CommonUtils isAllowedCamera] == NO) {        //无权限    UIAlertController *AlertController = [UIAlertController alertControllerWithTitle:@"“小满APP”想访问您的相机" message:@"需要您的同意，才能访问相机" preferredStyle:UIAlertControllerStyleAlert];        [AlertController addAction:[UIAlertAction actionWithTitle:@"去设置" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {                [[UIApplication sharedApplication] openURL:[NSURL URLWithString:UIApplicationOpenSettingsURLString]];    }]];    [AlertController addAction:[UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) {            }]];    //弹出提醒框；    [self presentViewController:AlertController animated:YES completion:nil];        return;}MGIDCardManager *cardManager = [[MGIDCardManager alloc] init];[cardManager IDCardStartDetection:weakSelf IdCardSide:IDCARD_SIDE_FRONT                           finish:^(MGIDCardModel *model) {                                                              [_cardInfoVC sendFaceIDCardRequest:[model croppedImageOfIDCard]];                           } errr:^(MGIDCardError) {                                                          }];

• 其中，croppedImageOfIDCard是为了从回调的model中取出图片：
• Face++SDK中的MGIDCardModel.mm

#pragma mark - Return UIImage- (UIImage *)croppedImageOfIDCard {#if TARGET_IPHONE_SIMULATOR    return nil;#else    return [self.result croppedImageOfIDCard];#endif}

• Face++SDK本地识别成功后，携带image向Face++后端请求代码（主要检验身份证合法性等等），请求成功之后我们才将身份证图片保存到本地：

- (void)sendFaceIDCardRequest:(UIImage *)image{    [KVNProgress showWithParameters:@{KVNProgressViewParameterStatus: @"加载中...",                                      KVNProgressViewParameterBackgroundType: @(KVNProgressBackgroundTypeSolid),                                      KVNProgressViewParameterFullScreen: @(NO)}];        UIImage *cardImage = image;    NSMutableDictionary *params = [NSMutableDictionary dictionary];    [params setObject:api_key forKey:@"api_key"];    [params setObject:api_secret forKey:@"api_secret"];    [params setObject:@"1" forKey:@"legality"];    __weak typeof(self) weakSelf = self;    [HYBNetworking uploadWithImage:cardImage url:QueryCardId filename:@"image"    name:@"image" mimeType:@"image/jpeg" parameters:params progress:^(int64_t bytesWritten, int64_t totalBytesWritten) {}    success:^(id response) {                [KVNProgress dismiss];        NSDictionary *dic = response;        NSLog(@"%@",[dic mj_JSONString]);        NSDictionary *legalityDict = [dic objectForKey:@"legality"];        NSString *side = [dic objectForKey:@"side"];            if ([side isEqualToString:@"back"]) {                        // 发证机关            self.cell.CREDITISSUEQRG = [dic objectForKey:@"issued_by"];            // valid_date 证件到期日            self.cell.CREDITCERTENDTIME  = [dic objectForKey:@"valid_date"];            [weakSelf saveImage:image withName:@"reverseCardImage.png"];                        weakSelf.cell.reverseCardImage = image;            [weakSelf.cell setClipReverseCardImage:image];            [weakSelf.cell setReverseCardImageDataInfo:legalityDict];                    }        else if ([side isEqualToString:@"front"]) {                        // 姓名            weakSelf.cell.nameTextField.text = [dic objectForKey:@"name"];            // 性别            //NSString *SEX = [dic objectForKey:@"race"];            // 证件号码            weakSelf.cell.IDCardTextField.text = [dic objectForKey:@"id_card_number"];            // 户籍所在地            weakSelf.cell.HOUSEHOLDADDR = [dic objectForKey:@"address"];                        NSString *CERTID = [CommonUtils getValueInUDWithKey:kCERTID];            if (![CommonUtils isStringNilOrEmpty:CERTID]) {                if (![CERTID isEqualToString:[dic objectForKey:@"id_card_number"]]) {                    [Toast showBottomWithText:@"您用的身份证与您实名的身份证不一致"];                    return;                }            }            // 升级UI            weakSelf.cell.positiveIDCardImage = image;//加载图片            [weakSelf.cell setClipPositiveIDCardImage:image];            [weakSelf.cell setPositiveIDCardImageDataInfo:legalityDict];                        // 出生年月//            NSDictionary *dict = [dic objectForKey:@"birthday"];//            NSString *day = [dict objectForKey:@"day"];//            NSString *month = [dict objectForKey:@"month"];//            NSString *year = [dict objectForKey:@"year"];                        [weakSelf saveImage:image withName:@"positiveIDCardImage.png"];        }            } fail:^(NSError *error) {        [KVNProgress dismiss];        [Toast showBottomWithText:kNetworkErrorMsg];    }];}

• 最后面有个saveImage: withName:就是向Face++请求成功之后，进行保存到本地操作。

#pragma mark - 保存图片至沙盒- (void)saveImage:(UIImage *)currentImage withName:(NSString *)imageName{    if ([imageName isEqualToString:@"positiveIDCardImage.png"]) {        NSString *imgPath = [CommonUtils pathFileDocDir:@"/BorrowProcess/positiveIDCardImage.png"];        if ([CommonUtils fileExistAtPath:imgPath]) {            [CommonUtils fileDel:imgPath];        }    }    if ([imageName isEqualToString:@"reverseCardImage.png"]) {        NSString *imgPath1 = [CommonUtils pathFileDocDir:@"/BorrowProcess/reverseCardImage.png"];        if ([CommonUtils fileExistAtPath:imgPath1]) {            [CommonUtils fileDel:imgPath1];        }    }        float kCompressionQuality = 0.5;    NSData *imageData = UIImageJPEGRepresentation(currentImage, kCompressionQuality);  //将图片压缩        NSString *fullPath = [[NSHomeDirectory() stringByAppendingPathComponent:@"Documents/BorrowProcess/"] stringByAppendingPathComponent:imageName];  //获取沙盒目录        //创立文件夹    [self createFile];    //保存图片    BOOL _isWriteToFile = [imageData writeToFile:fullPath atomically:YES];  //将图片写入文件}

2. 上传回调图片

通过上面的保存操作，现在我们的APP到了点击下一步的情形，这时候需要我们向自己的后端（不是Face++的后端）上传图片了。

2.1 调使用HYBNetworking的上传图片API

上传图片API

+ (HYBURLSessionTask *)uploadWithImage:(UIImage *)image                                   url:(NSString *)url                              filename:(NSString *)filename                                  name:(NSString *)name                              mimeType:(NSString *)mimeType                            parameters:(NSDictionary *)parameters                              progress:(HYBUploadProgress)progress                               success:(HYBResponseSuccess)success                                  fail:(HYBResponseFail)fail 

调使用示例

#pragma mark - 上传身份证正面//请求接口-(void)httpRequestFRONT{    NSString *LOANAPPLICATIONNO = nil;    NSMutableArray *dataArray = [self seekPlist];    if (dataArray) {        NSDictionary *dataDict = nil;        for (NSDictionary *dict in dataArray) {            NSInteger index = [[dict objectForKey:@"index"] integerValue];            if (index == 0) {                if (dict) {                    dataDict = dict;                }            }        }                NSDictionary *dd = [dataDict objectForKey:@"BorrowProcess"];        LOANAPPLICATIONNO = [dd objectForKey:@"LOANAPPLICATIONNO"];    }    if ([CommonUtils isStringNilOrEmpty:LOANAPPLICATIONNO]) {        LOANAPPLICATIONNO = @"";    }        NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);    NSString *path = [paths objectAtIndex:0];    NSString *fileName = @"positiveIDCardImage";    NSString *filePath = [NSString stringWithFormat:@"%@/BorrowProcess/%@.png", path, fileName];    UIImage *image;    if ([self isFileExist:fileName] == YES)    {        //显示本地缓存        image = [UIImage imageWithContentsOfFile:filePath];            }    [CommonUtils saveStrValueInUD:@"status016" forKey:kTRANSCODE];        [KVNProgress showWithParameters:@{KVNProgressViewParameterStatus: @"加载中...",                                      KVNProgressViewParameterBackgroundType: @(KVNProgressBackgroundTypeSolid),                                      KVNProgressViewParameterFullScreen: @(NO)}];    NSMutableDictionary *params = [NSMutableDictionary dictionary];            [params setObject:[CommonUtils getStrValueInUDWithKey:kTOKEN] forKey:@"TOKEN"];    // 使用户账号    [params setObject:[CommonUtils getStrValueInUDWithKey:kUSERNO] forKey:@"USERNO"];            //    NSArray *BUSINESSTYPE = @[];//文档编号    //    NSArray *BUSINESSNO = @[];//业务编号    //    NSArray *DOCTYPE = @[];//文档类型    [params setObject:@"LOAN_APPLY" forKey:@"BUSINESSTYPE"];    [params setObject:LOANAPPLICATIONNO forKey:@"BUSINESSNO"];    [params setObject:@"IDCARD_FRONT_APP" forKey:@"DOCTYPE"];        __weak typeof(self) weakSelf = self;        //上传图片    [HYBNetworking uploadWithImage:image url:uploadImage filename:@"IDFrontImage.jpg" name:@"FILE" mimeType:@"image/jpeg" parameters:params progress:^(int64_t bytesWritten, int64_t totalBytesWritten) {        //获取进度：bytesWritten/totalBytesWritten    } success:^(id response) {                [KVNProgress dismiss];                typeof(weakSelf) strongSelf = weakSelf;        NSString *stringData = [response mj_JSONString];        stringData = [DES3Util decrypt:stringData];        NSLog(@"stirngData: %@", stringData);                NSDictionary *responDict = [stringData mj_JSONObject];        NSString *RETCODE = [responDict objectForKey:@"RETCODE"];        if ([RETCODE isEqualToString:kSUCCESS]) {                        [strongSelf httpRequestBACK];        }else if([RETCODE isEqualToString:kROKEN]){            NSDictionary *processdict = @{@"index":[NSNumber numberWithInteger:10], @"showProcessView":[NSNumber numberWithBool:YES]};            [[NSNotificationCenter defaultCenter] postNotificationName:kBorrowProcessNotication object:nil userInfo:processdict];        }else{            NSString *RETMSG = [responDict objectForKey:@"RETMSG"];            if (![CommonUtils isStringNilOrEmpty:RETMSG]) {                [Toast showBottomWithText:RETMSG];            }        }    } fail:^(NSError *error) {        [KVNProgress dismiss];        [Toast showBottomWithText:kNetworkErrorMsg];    }];}

2.2 调使用AFNetwork整合图片的API — 暨HYBNetworing上传图片封装源码解析

整合图片API

- (void)appendPartWithFileData:(NSData *)data                          name:(NSString *)name                      fileName:(NSString *)fileName                      mimeType:(NSString *)mimeType

调使用示例 — 上述2.1节中HYBNetworking的上传图片其实是调使用AFNetworking的上传图片API。所以，HYBNetworking框架中上传图片的源码实现就是调使用AFNetworking上传图片API的一个示例：

• HYBNetworking.m

+ (HYBURLSessionTask *)uploadWithImage:(UIImage *)image                                   url:(NSString *)url                              filename:(NSString *)filename                                  name:(NSString *)name                              mimeType:(NSString *)mimeType                            parameters:(NSDictionary *)parameters                              progress:(HYBUploadProgress)progress                               success:(HYBResponseSuccess)success                                  fail:(HYBResponseFail)fail {  if ([self baseUrl] == nil) {    if ([NSURL URLWithString:url] == nil) {      HYBAppLog(@"URLString无效，无法生成URL。可能是URL中有中文，请尝试Encode URL");      return nil;    }  } else {    if ([NSURL URLWithString:[NSString stringWithFormat:@"%@%@", [self baseUrl], url]] == nil) {      HYBAppLog(@"URLString无效，无法生成URL。可能是URL中有中文，请尝试Encode URL");      return nil;    }  }    if ([self shouldEncode]) {    url = [self encodeUrl:url];  }    NSString *absolute = [self absoluteUrlWithPath:url];    AFHTTPSessionManager *manager = [self manager];  HYBURLSessionTask *session = [manager POST:url parameters:parameters constructingBodyWithBlock:^(id<AFMultipartFormData>  _Nonnull formData) {    NSData *imageData = UIImageJPEGRepresentation(image, 1);        NSString *imageFileName = filename;    if (filename == nil || ![filename isKindOfClass:[NSString class]] || filename.length == 0) {      NSDateFormatter *formatter = [[NSDateFormatter alloc] init];      formatter.dateFormat = @"yyyyMMddHHmmss";      NSString *str = [formatter stringFromDate:[NSDate date]];      imageFileName = [NSString stringWithFormat:@"%@.jpg", str];    }        // 整合图片，以文件流的格式    [formData appendPartWithFileData:imageData name:name fileName:imageFileName mimeType:mimeType];  } progress:^(NSProgress * _Nonnull uploadProgress) {    if (progress) {      progress(uploadProgress.completedUnitCount, uploadProgress.totalUnitCount);    }  } success:^(NSURLSessionDataTask * _Nonnull task, id  _Nullable responseObject) {    [[self allTasks] removeObject:task];    [self successResponse:responseObject callback:success];        if ([self isDebug]) {      [self logWithSuccessResponse:responseObject                               url:absolute                            params:parameters];    }  } failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {    [[self allTasks] removeObject:task];        [self handleCallbackWithError:error fail:fail];        if ([self isDebug]) {      [self logWithFailError:error url:absolute params:nil];    }  }];    [session resume];  if (session) {    [[self allTasks] addObject:session];  }    return session;}

可见，整合图片的一句关键代码在

// 整合图片，以文件流的格式[formData appendPartWithFileData:imageData name:name fileName:imageFileName mimeType:mimeType];

这里是设置图片的数据流，作为AFNetwork的POST请求方法的一个constructingBodyWithBlock参数的输入。

AFNetwork的POST请求方法源码

• AFHTTPSessionManager.m

- (NSURLSessionDataTask *)POST:(NSString *)URLString                    parameters:(id)parameters     constructingBodyWithBlock:(void (^)(id <AFMultipartFormData> formData))block                      progress:(nullable void (^)(NSProgress * _Nonnull))uploadProgress                       success:(void (^)(NSURLSessionDataTask *task, id responseObject))success                       failure:(void (^)(NSURLSessionDataTask *task, NSError *error))failure{    NSError *serializationError = nil;    NSMutableURLRequest *request = [self.requestSerializer multipartFormRequestWithMethod:@"POST" URLString:[[NSURL URLWithString:URLString relativeToURL:self.baseURL] absoluteString] parameters:parameters constructingBodyWithBlock:block error:&serializationError];    if (serializationError) {        if (failure) {            dispatch_async(self.completionQueue ?: dispatch_get_main_queue(), ^{                failure(nil, serializationError);            });        }        return nil;    }    __block NSURLSessionDataTask *task = [self uploadTaskWithStreamedRequest:request progress:uploadProgress completionHandler:^(NSURLResponse * __unused response, id responseObject, NSError *error) {        if (error) {            if (failure) {                failure(task, error);            }        } else {            if (success) {                success(task, responseObject);            }        }    }];    [task resume];    return task;}

这个方法将block传递给下一个API，并返回一个request：

• AFURLRequestSerialization.m

- (NSMutableURLRequest *)multipartFormRequestWithMethod:(NSString *)method                                              URLString:(NSString *)URLString                                             parameters:(NSDictionary *)parameters                              constructingBodyWithBlock:(void (^)(id <AFMultipartFormData> formData))block                                                  error:(NSError *__autoreleasing *)error{    NSParameterAssert(method);    NSParameterAssert(![method isEqualToString:@"GET"] && ![method isEqualToString:@"HEAD"]);    NSMutableURLRequest *mutableRequest = [self requestWithMethod:method URLString:URLString parameters:nil error:error];    __block AFStreamingMultipartFormData *formData = [[AFStreamingMultipartFormData alloc] initWithURLRequest:mutableRequest stringEncoding:NSUTF8StringEncoding];    if (parameters) {        for (AFQueryStringPair *pair in AFQueryStringPairsFromDictionary(parameters)) {            NSData *data = nil;            if ([pair.value isKindOfClass:[NSData class]]) {                data = pair.value;            } else if ([pair.value isEqual:[NSNull null]]) {                data = [NSData data];            } else {                data = [[pair.value description] dataUsingEncoding:self.stringEncoding];            }            if (data) {                [formData appendPartWithFormData:data name:[pair.field description]];            }        }    }    if (block) {        block(formData);    }    return [formData requestByFinalizingMultipartFormData];}

• 这个方法的关键在于最后，使用block回调了formData：

if (block) {        block(formData);    }

这个formData是一个AFStreamingMultipartFormData模型的对象

图片模型 — AFStreamingMultipartFormData

• AFURLRequestSerialization.m

@interface AFStreamingMultipartFormData ()@property (readwrite, nonatomic, copy) NSMutableURLRequest *request;@property (readwrite, nonatomic, assign) NSStringEncoding stringEncoding;@property (readwrite, nonatomic, copy) NSString *boundary;@property (readwrite, nonatomic, strong) AFMultipartBodyStream *bodyStream;@end

这样，就执行了前面调使用时block里面的图片数据整合操作（[formData appendPartWithFileData…];）。

图片数据整合操作

在multipartFormRequestWithMethod:...的实现代码中，接着，利使用block体中设置好的formData，调使用下述的requestByFinalizingMultipartFormData方法以返回一个request，而后进行请求。requestByFinalizingMultipartFormData的代码如下：

• AFURLRequestSerialization.m

- (NSMutableURLRequest *)requestByFinalizingMultipartFormData {    if ([self.bodyStream isEmpty]) {        return self.request;    }    // Reset the initial and final boundaries to ensure correct Content-Length    [self.bodyStream setInitialAndFinalBoundaries];    [self.request setHTTPBodyStream:self.bodyStream];    [self.request setValue:[NSString stringWithFormat:@"multipart/form-data; boundary=%@", self.boundary] forHTTPHeaderField:@"Content-Type"];    [self.request setValue:[NSString stringWithFormat:@"%llu", [self.bodyStream contentLength]] forHTTPHeaderField:@"Content-Length"];    return self.request;}

上面代码的关键在于将图片数据整合进request，设置HTTPBodyStream，即[self.request setHTTPBodyStream:self.bodyStream];。

• 获取上述request之后，如前面所述“ AFNetwork的POST请求方法源码”，调使用返回request的API之后，再调使用POST请求方法进行请求操作，即__block NSURLSessionDataTask *task = [self uploadTaskWithStreamedRequest:request progress:uploadProgress completionHandler:^(NSURLResponse * __unused response, id responseObject, NSError *error) {这一句。

获取带有图片request的API

- (NSMutableURLRequest *)multipartFormRequestWithMethod:(NSString *)method                                              URLString:(NSString *)URLString                                             parameters:(NSDictionary *)parameters                              constructingBodyWithBlock:(void (^)(id <AFMultipartFormData> formData))block                                                  error:(NSError *__autoreleasing *)error

上传带有图片request的API

- (NSURLSessionUploadTask *)uploadTaskWithStreamedRequest:(NSURLRequest *)request                                                 progress:(void (^)(NSProgress *uploadProgress)) uploadProgressBlock                                        completionHandler:(void (^)(NSURLResponse *response, id responseObject, NSError *error))completionHandler

2.3 源码分析 — AFNetwork整合图片数据调使用栈解析

• 将形容图片的参数字符串转化头字典

- (void)appendPartWithFileData:(NSData *)data                          name:(NSString *)name                      fileName:(NSString *)fileName                      mimeType:(NSString *)mimeType{    NSParameterAssert(name);    NSParameterAssert(fileName);    NSParameterAssert(mimeType);    NSMutableDictionary *mutableHeaders = [NSMutableDictionary dictionary];    [mutableHeaders setValue:[NSString stringWithFormat:@"form-data; name=\"%@\"; filename=\"%@\"", name, fileName] forKey:@"Content-Disposition"];    [mutableHeaders setValue:mimeType forKey:@"Content-Type"];    [self appendPartWithHeaders:mutableHeaders body:data];}

• 为图片数据增加头字典 — 数据整合

- (void)appendPartWithHeaders:(NSDictionary *)headers                         body:(NSData *)body{    NSParameterAssert(body);    AFHTTPBodyPart *bodyPart = [[AFHTTPBodyPart alloc] init];    bodyPart.stringEncoding = self.stringEncoding;    bodyPart.headers = headers;    bodyPart.boundary = self.boundary;    bodyPart.bodyContentLength = [body length];    bodyPart.body = body;    [self.bodyStream appendHTTPBodyPart:bodyPart];}

其中，数据流self.bodyStream是这样定义的：

@property (readwrite, nonatomic, strong) AFMultipartBodyStream *bodyStream;

其中，AFMultipartBodyStream是这样定义的：

@interface AFMultipartBodyStream : NSInputStream <NSStreamDelegate>

• 再来看看怎么向数据流增加整合好的图片数据的：

- (void)appendHTTPBodyPart:(AFHTTPBodyPart *)bodyPart {    [self.HTTPBodyParts addObject:bodyPart];}

• 其中，HTTPBodyParts是这样定义的：

@property (readwrite, nonatomic, strong) NSMutableArray *HTTPBodyParts;

• 另外，AFHTTPBodyPart的定义是这样的：

@interface AFHTTPBodyPart : NSObject@property (nonatomic, assign) NSStringEncoding stringEncoding;@property (nonatomic, strong) NSDictionary *headers;@property (nonatomic, copy) NSString *boundary;@property (nonatomic, strong) id body;@property (nonatomic, assign) unsigned long long bodyContentLength;@property (nonatomic, strong) NSInputStream *inputStream;@property (nonatomic, assign) BOOL hasInitialBoundary;@property (nonatomic, assign) BOOL hasFinalBoundary;@property (readonly, nonatomic, assign, getter = hasBytesAvailable) BOOL bytesAvailable;@property (readonly, nonatomic, assign) unsigned long long contentLength;

3. XMNetworking

XMNetworking其实也是基于ANNetwork封装的，不过封装的层级比HYBNetworking多，看起来有点隐晦。这里分析一下XMNetworking上传图片的API。

3.1 整合图片

• 整合图片API

- (void)addFormDataWithName:(NSString *)name fileName:(NSString *)fileName mimeType:(NSString *)mimeType fileData:(NSData *)fileData 

• 调使用示例

- (NSString *_Nullable)uploadWithUploadImageModels:(nullable NSArray<UploadImageModel *> *)imageModelArr params:(id _Nullable )params paramsType:(ParamsType)paramsType userNo:(NSString *)userNo APITag:(API_Tag)tag mimeType:(nullable NSString *)mimeType       OnSuccess:(SuccessBlock)successBlock onFailure:(FailureBlock)failureBlock{    NSString *identifier = [XMCenter sendRequest:^(XMRequest * _Nonnull request) {                request.api = [self pathURLWithAPITag:tag];                if ([self respondsToSelector:@selector(cys_requestOnlyLayerParameters:)]) {            request.parameters = [self cys_requestOnlyLayerParameters:params];        }                // 上传图片，以文件流的格式        for (UploadImageModel *imageModel in imageModelArr) {            NSData *imageData = UIImageJPEGRepresentation(imageModel.image, 0.5);                        NSString *imageFileName = imageModel.fileName;            if (imageModel.fileName == nil || ![imageModel.fileName isKindOfClass:[NSString class]] || imageModel.fileName.length == 0) {                NSDateFormatter *formatter = [[NSDateFormatter alloc] init];                formatter.dateFormat = @"yyyyMMddHHmmss";                NSString *str = [formatter stringFromDate:[NSDate date]];                imageFileName = [NSString stringWithFormat:@"%@.jpg", str];            }            // 上传图片            [request addFormDataWithName:imageModel.name fileName:imageFileName mimeType:mimeType fileData:imageData];        }                NSLog(@"请求的参数：%@",request.parameters);        if (imageModelArr.count > 0) {            request.requestType = kXMRequestUpload;        }        request.requestSerializerType = kXMRequestSerializerJSON;    } onSuccess:^(id  _Nullable responseObject) {        // 省略...

3.2 上传图片API源码解析

• 将整合好的图片数据formData增加到图片模型数组uploadFormDatas

- (void)addFormDataWithName:(NSString *)name fileName:(NSString *)fileName mimeType:(NSString *)mimeType fileData:(NSData *)fileData {            XMUploadFormData *formData = [XMUploadFormData formDataWithName:name fileName:fileName mimeType:mimeType fileData:fileData];    [self.uploadFormDatas addObject:formData];}

• 整合图片数据

+ (instancetype)formDataWithName:(NSString *)name fileName:(NSString *)fileName mimeType:(NSString *)mimeType fileData:(NSData *)fileData {    XMUploadFormData *formData = [[XMUploadFormData alloc] init];    formData.name = name;    formData.fileName = fileName;    formData.mimeType = mimeType;    formData.fileData = fileData;    return formData;}

• 图片模型数组

- (NSMutableArray<XMUploadFormData *> *)uploadFormDatas {    if (!_uploadFormDatas) {        _uploadFormDatas = [NSMutableArray array];    }    return _uploadFormDatas;}

• 图片模型 — XMUploadFormData

/** `XMUploadFormData` is the class for describing and carring the upload file data, see `AFMultipartFormData` protocol for details. */@interface XMUploadFormData : NSObject/** The name to be associated with the specified data. This property must not be `nil`. */@property (nonatomic, copy) NSString *name;/** The file name to be used in the `Content-Disposition` header. This property is not recommended be `nil`. */@property (nonatomic, copy, nullable) NSString *fileName;/** The declared MIME type of the file data. This property is not recommended be `nil`. */@property (nonatomic, copy, nullable) NSString *mimeType;/** The data to be encoded and appended to the form data, and it is prior than `fileURL`. */@property (nonatomic, strong, nullable) NSData *fileData;/** The URL corresponding to the file whose content will be appended to the form, BUT, when the `fileData` is assigned，the `fileURL` will be ignored. */@property (nonatomic, strong, nullable) NSURL *fileURL;// NOTE: Either of the `fileData` and `fileURL` should not be `nil`, and the `fileName` and `mimeType` must both be `nil` or assigned at the same time,

• 遍历图片模型数组中的图片模型进行上传请求

- (void)xm_uploadTaskWithRequest:(XMRequest *)request               completionHandler:(XMCompletionHandler)completionHandler {        AFHTTPSessionManager *sessionManager = [self xm_getSessionManager:request];    AFHTTPRequestSerializer *requestSerializer = [self xm_getRequestSerializer:request];        __block NSError *serializationError = nil;    NSMutableURLRequest *urlRequest = [requestSerializer multipartFormRequestWithMethod:@"POST"                                                                              URLString:request.url                                                                             parameters:request.parameters                                                              constructingBodyWithBlock:^(id<AFMultipartFormData> formData) {        [request.uploadFormDatas enumerateObjectsUsingBlock:^(XMUploadFormData *obj, NSUInteger idx, BOOL *stop) {            if (obj.fileData) {                if (obj.fileName && obj.mimeType) {                    [formData appendPartWithFileData:obj.fileData name:obj.name fileName:obj.fileName mimeType:obj.mimeType];                } else {                    [formData appendPartWithFormData:obj.fileData name:obj.name];                }            } else if (obj.fileURL) {                NSError *fileError = nil;                if (obj.fileName && obj.mimeType) {                    [formData appendPartWithFileURL:obj.fileURL name:obj.name fileName:obj.fileName mimeType:obj.mimeType error:&fileError];                } else {                    [formData appendPartWithFileURL:obj.fileURL name:obj.name error:&fileError];                }                if (fileError) {                    serializationError = fileError;                    *stop = YES;                }            }        }];    } error:&serializationError];        if (serializationError) {        if (completionHandler) {            dispatch_async(xm_request_completion_callback_queue(), ^{                completionHandler(nil, serializationError);            });        }        return;    }        [self xm_processURLRequest:urlRequest byXMRequest:request];        NSURLSessionUploadTask *uploadTask = nil;    __weak __typeof(self)weakSelf = self;    uploadTask = [sessionManager uploadTaskWithStreamedRequest:urlRequest                                                           progress:request.progressBlock                                                  completionHandler:^(NSURLResponse *response, id responseObject, NSError *error) {        __strong __typeof(weakSelf)strongSelf = weakSelf;        [strongSelf xm_processResponse:response                                object:responseObject                                 error:error                               request:request                     completionHandler:completionHandler];    }];        [self xm_setIdentifierForReqeust:request taskIdentifier:uploadTask.taskIdentifier sessionManager:sessionManager];    [uploadTask bindingRequest:request];    [uploadTask resume];}

• 可见，XMNetworking最后还是调使用AFNetwork的POST请求及uploadTaskWithStreamedRequest方法进行上传。

- (NSMutableURLRequest *)multipartFormRequestWithMethod:(NSString *)method                                              URLString:(NSString *)URLString                                             parameters:(NSDictionary *)parameters                              constructingBodyWithBlock:(void (^)(id <AFMultipartFormData> formData))block                                                  error:(NSError *__autoreleasing *)error

• 同样可见，同HYBNetworking一样，调使用AFNetworking的图片数据整合API appendPartWithFileData:进行设置

[formData appendPartWithFileData:obj.fileData name:obj.name fileName:obj.fileName mimeType:obj.mimeType];

4. 总结：上传图片逻辑整理

AFNetwork

• 压缩转换：UIImage实例对象通过UIImageJPEGRepresentation压缩转换为NSData，下面称之为imageData。
• 信息整合：将imageData与文件名fileName，文件路径name，类型名mimeType整合成图片模型（AFHTTPBodyPart）的一个对象bodyPart中去。
• 增加图片模型：将上面新建好的图片模型对象bodyPart，向图片输入流（AFMultipartBodyStream）的对象bodyStream的数组属性（HTTPBodyParts）增加。
• 设置requet的HTTPBodyStream属性为bodyStream：封装为requestByFinalizingMultipartFormData
• 将图片模型对象formData使用AFNetwork的POST请求与uploadTaskWithStreamedRequest方法进行上传。

HYBNetworking

• 压缩转换：UIImage实例对象通过UIImageJPEGRepresentation压缩转换为NSData，下面称之为imageData。
• 信息整合：利使用AFNetwork的appendPartWithFileData，将imageData与文件名fileName，文件路径name，类型名mimeType整合成图片模型（AFStreamingMultipartFormData）的一个对象formData中去。
• 将图片模型对象formData使用AFNetwork的POST请求与uploadTaskWithStreamedRequest方法进行上传。

XMNetworking

• 压缩转换：UIImage实例对象通过UIImageJPEGRepresentation压缩转换为NSData，下面称之为imageData。
• 信息整合：利使用AFNetwork的appendPartWithFileData，将imageData与文件名fileName，文件路径name，类型名mimeType整合成图片模型（XMUploadFormData）的一个对象formData中去。
• 增加图片模型：向管理器的图片模型数组uploadFormDatas增加上面新建好的图片模型对象formData。
• 遍历图片模型数组，取得图片模型，利使用AFNetwork的POST请求与uploadTaskWithStreamedRequest方法进行上传。

5. 说明

本文示例只做了最简单的请求方式 — 发起一次请求就调使用一次。

其实，还有很多可以优化的点，例如，对所有request进行管理封装：建立一个请求的队列或者者数组，相同请求不允许再增加，优先级低的请求先等待，异步请求的最大并发线程数，等等。这里只提示，就不详情了。