如何使用阻止套接字API添加消息发送操作(smtp)的进度? [英] How can I add a progress for message sending operation (smtp) with blocking sockets API's?

问题描述

我正在使用阻塞套接字API(waitFor *函数)通过​​smtp协议(这是DLL模式)发送邮件.所有操作都是同步的:connect->waitForConnected(timeout)->login->waitForReadyRead(timeout)->sendMessage->waitForBytesWritten(timeout)-> etc. 我正在使用阻止API，因为需要QCoreApplication缺少(不同应用程序使用的DLL，包括基于非qt的应用程序).阻塞函数不需要事件循环，并且可以正常工作. 但是，如何对长期发送邮件操作(例如带有大附件)进行可视化处理? 以及如何在sendmail DLL中组织用于进度通知的回调? ps:所有阻塞的waitFor *函数都标记为 功能，在Windows上可能会随机失败.如果您的软件将在Windows上运行，请考虑使用事件循环和readyRead()信号. 为什么?

I'm using blocking sockets API (waitFor* functions) for sending mail by smtp protocol (it's a DLL modue). All operations are synchronous: connect->waitForConnected(timeout)->login->waitForReadyRead(timeout)->sendMessage->waitForBytesWritten(timeout)->etc. I'm using blocking API, because QCoreApplication absence is required (DLL used by different apps, incl. non-qt-based). Blocking functions don't require event loop and it works fine. But how can I make a visual progress for long-term sending mail operations (with big attachment, for example)? And how can organize callbacks for progress notifications in sendmail DLL? ps: all blocking waitFor* functions marked as functions, that may fail randomly on Windows. Consider using the event loop and the readyRead() signal if your software will run on Windows. Why?

推荐答案

在使用DLL时，您绝对可以拥有QApplication实例(因为您要使用基于窗口小部件的gui，因此必须为QApplication而不是QCoreApplication).它集成到主线程的本机消息循环中.请记住，要运行Qt Gui，您只需要一个本机事件循环-不必将代码停留在QCoreApplication::exec中.您需要该应用程序的实例，并且需要通过调用一次exec并确保它返回(即通过使用零超时计时器)来启动它，但是仅此而已.除此之外，应用程序的主线程的消息泵将为您处理事情.

You can definitely have a QApplication instance when using DLLs (it must be QApplication not QCoreApplication since you want a widget-based gui). It integrates into the native message loop of the main thread. Remember that for Qt Gui to run you only need a native event loop - the code doesn't have to be stuck within QCoreApplication::exec. You need an instance of the application, and you need to prime it by invoking exec once, and ensuring that it returns (i.e. by using a zero-timeout timer), but that's all. Past that, the application's main thread's message pump will handle things for you.

此外，要使用网络API，您无需卡在主线程中-您可以在单独的线程中处理它们.

Furthermore, to use networking APIs, you don't need to be stuck in the main thread - you can handle them in a separate thread.

您的DLL与不会在主线程中运行消息泵的控制台应用程序不兼容，但是您可以作弊:仅在Windows上，QCoreApplication及其派生类可以是在任何线程中使用:)

Your DLL won't be compatible with console applications that don't run a message pump in the main thread, but then you can cheat: on Windows, and on Windows only, the QCoreApplication and its derived classes can be used in any thread :)

您绝对必须将DLL与Qt静态链接，或使用放置在唯一名称空间中的动态链接Qt.请记住，如果您链​​接的应用程序使用Qt，则绝对不能保证它们构建的Qt与您使用的Qt二进制兼容.即使是相同的版本.

You definitely must either statically link your DLL with Qt, or use a dynamically-linked Qt that was put in a unique namespace. Remember that if the application you link with uses Qt, there are absolutely no guarantees that the Qt they built is binary-compatible with the Qt that you use. Even if it's the same version.

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