iOS MAilCore：如何下载邮件附件并在 web 视图中显示？答案

【问题标题】：iOS MAilCore: How can i download mail attachments and show it in a webview?iOS MAilCore：如何下载邮件附件并在 web 视图中显示？
【发布时间】：2013-07-27 12:22:10
【问题描述】：

我是 iOS 开发的新手。我正在使用 MailCore 在我的应用程序中接收电子邮件。我的 xcode 版本是 4.6.3 和 iOS：6.1 和 5.1。谁能帮我解决我的问题。我从我的服务器收到带有附件计数和描述的邮件，但我没有找到下载此文件的方法或我如何获取附件。

请帮帮我。

谢谢！

【问题讨论】：

标签： iphone ios email ios6 mailcore

【解决方案1】：

很简单：

首先——获取消息的uid

MCOIndexSet *uidSet = [MCOIndexSet indexSetWithRange:MCORangeMake(1,UINT64_MAX)];//for all msgs
MCOIMAPSession *session = <new or reuse IMAP session, i reuse this>
MCOIMAPFetchMessagesOperation *fetchOp =
[session fetchMessagesByUIDOperationWithFolder:@"INBOX"
                                    requestKind:MCOIMAPMessagesRequestKindFullHeaders
                                           uids:uidSet];

[fetchOp start:^(NSError *err, NSArray *messagesList, MCOIndexSet *vanished) {
    if (!err) {            
        NSLog(@"Receive %i messages",(int)[messagesList count]);
        NSSortDescriptor *sort = [NSSortDescriptor sortDescriptorWithKey:@"header.date" ascending:NO];
//upd UI
        [[NSNotificationCenter defaultCenter] postNotificationName:kNotif_postCollector_ReceiveMessages object:nil];
//store msgs
        [[DataSingleton sharedSingleton] updateMessageListWithMessages:[messagesList sortedArrayUsingDescriptors:@[sort]]];
    }else{
        //oh no
    }
}];

第二 - 获取消息的结构（不是全部，只需要 - 数组消息列表）

MCOIndexSet *uidSet = [MCOIndexSet indexSet];
for (Message *message in messagesList)// i use this class to store msgs. mcUid = MailCore Uid
    [uidSet addIndex:[[message mcUid] integerValue]];

MCOIMAPSession *session = <new or reuse IMAP session, i reuse this>
MCOIMAPFetchMessagesOperation *fetchOp =
[session fetchMessagesByUIDOperationWithFolder:@"INBOX"//or another folder
                                   requestKind:MCOIMAPMessagesRequestKindStructure
                                          uids:uidSet];

[fetchOp start:^(NSError *err, NSArray *messagesList, MCOIndexSet *vanished) {

    if (!err) {

        NSLog(@"Receive %i messages with structures",(int)[messagesList count]);
        NSSortDescriptor *sort = [NSSortDescriptor sortDescriptorWithKey:@"header.date" ascending:NO];
        //store attachment precence
        [[DataSingleton sharedSingleton] updateAttachmentsPresenceForMessages:[messagesList sortedArrayUsingDescriptors:@[sort]]
                                                            forAccount:acc];
/* You get array of this objects:
MCOIMAPPart : MCOAbstractPart
//A part identifier looks like 1.2.1
@property (nonatomic, copy) NSString * partID;
//The size of the single part in bytes
@property (nonatomic, nonatomic) unsigned int size;
//It's the encoding of the single part
@property (nonatomic, nonatomic) MCOEncoding encoding;
*/
    }
}];

第三步和最后一步：

MCOIMAPSession *session = <new or reuse IMAP session, i reuse this>
int uid = [[message mcUid] intValue];
NSString *partID = [attachment mcPartID];//we stored it on step 2
MCOIMAPFetchContentOperation * op = [session     fetchMessageAttachmentByUIDOperationWithFolder:@"INBOX"
  uid:uid
  partID:partID
  encoding:(MCOEncoding)[[attachment mcEncoding] integerValue]];

NSLog(@"download att %i part %@",uid,partID);
[op start:^(NSError * error, NSData * messageData) {

    if (error) {

    }else{
        TRACE(@"receive att %i part %@",uid,partID);
        //save attachment fo local disc
        [[DataSingleton sharedSingleton] updateDownloadedAttachment:attachment
                                                           withData:messageData];
    }
}];

更多信息在GitHub和官方页面libmailcore.com

【讨论】：

您好，您可以发布您的 DataSingleton 课程吗？谢谢
@sundsx 抱歉，没有。它受 NDA 保护。你想知道什么？
嗨，winsergey。我想按照您的示例存储附件。例如：updateAttachmentsPresenceForMessages 和 updateDownloadedAttachment 是数组还是 nsdata 对象？
@sundsx 回答你的问题：gist.github.com/b5684c470e877af75880 gist.github.com/ba53ef49818ea6db79be
你是个大人物！谢谢 WINSergey。

【解决方案2】：

            MCOMessageParser * msg = [MCOMessageParser messageParserWithData:data];

            if ([_message.attachments count] > 0)
            {
                for (int i=0; i<[_message.attachments count]; ++i)
                {
                    MCOIMAPPart *part = [_message.attachments objectAtIndex:i];

                    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
                    NSString *docDir = [paths objectAtIndex:0];
                    NSString *filePath = [NSString stringWithFormat:@"%@/%@",
                                          docDir, [part filename]];
                    BOOL fileExists = [[NSFileManager defaultManager] fileExistsAtPath:filePath];
                    if (NO == fileExists) {
                        [data writeToFile:filePath atomically:YES];
                    }
                }
            }

【讨论】：