如何在PHP当前时间延迟30秒？(How to get delay of 30 sec in current time in php?)

 如果这是从昨天起你的项目的延续，你已经在内存中有你的下载列表 - 只需在他们的进程完成下载时从加载的列表中删除条目，并且只有在你退出''时才在输入文件中写下整个列表。下载”。 没有理由不断写下这些变化。 
 
 如果你想知道（比如来自外部进程），即使在你的'下载程序'运行时也会下载url，每次进程返回下载成功时，在downloaded.dat写一个新行。 
 
 当然，在这两种情况下，从主进程/线程中写入，这样您就不必担心互斥锁。 
 
 更新 - 以下是如何使用与昨天相同的代码库使用其他文件： 
 
def init_downloader(params):  # our downloader initializator
    downloader = Downloader(**params[0])  # instantiate our downloader
    downloader.run(params[1])  # run our downloader
    return params  # job finished, return the same params for identification

if __name__ == "__main__":  # important protection for cross-platform use

    downloader_params = [  # Downloaders will be initialized using these params
        {"port_number": 7751},
        {"port_number": 7851},
        {"port_number": 7951}
    ]
    downloader_cycle = cycle(downloader_params)  # use a cycle for round-robin distribution

    with open("downloaded_links.dat", "a+") as diff_file:  # open your diff file
        diff_file.seek(0)  # rewind the diff file to the beginning to capture all lines
        diff_links = {row.strip() for row in diff_file}  # load downloaded links into a set
        with open("input_links.dat", "r+") as input_file:  # open your input file
            available_links = []
            download_jobs = []  # store our downloader parameters + a link here
            # read our file line by line and filter out downloaded links
            for row in input_file:  # loop through our file
                link = row.strip()  # remove the extra whitespace to get the link
                if link not in diff_links:  # make sure link is not already downloaded
                    available_links.append(row)
                    download_jobs.append([next(downloader_cycle), link])
            input_file.seek(0)  # rewind our input file
            input_file.truncate()  # clear out the input file
            input_file.writelines(available_links)  # store back the available links
            diff_file.seek(0)  # rewind the diff file
            diff_file.truncate()  # blank out the diff file now that the input is updated
        # and now let's get to business...
        if download_jobs:
            download_pool = Pool(processes=5)  # make our pool use 5 processes
            # run asynchronously so we can capture results as soon as they ar available
            for response in download_pool.imap_unordered(init_downloader, download_jobs):
                # since it returns the same parameters, the second item is a link
                # add the link to our `diff` file so it doesn't get downloaded again
                diff_file.write(response[1] + "\n")
        else:
            print("Nothing left to download...")
 
 正如我在评论中所写的那样，整个想法是在下载链接时使用文件存储下载的链接，然后在下次运行时过滤掉下载的链接并更新输入文件。 这样即使你强行杀死它，它也会一直从它停止的地方恢复（部分下载除外）。 

If this is a continuation of your project from yesterday you already have your download list in memory - just remove the entries from the loaded list as their processes finish download and only write down the whole list over the input file once you're exiting the 'downloader'. There is no reason to constantly write down the changes.
 
If you want to know (say from an external process) when a url gets downloaded even while your 'downloader' is running, write in a downloaded.dat a new line each time a process returns that download was successful.
 
Of course, in both cases, write from within your main process/thread so you don't have to worry about mutex.
 
UPDATE - Here's how to do it with an additional file, using the same code base as yesterday:
 
def init_downloader(params):  # our downloader initializator
    downloader = Downloader(**params[0])  # instantiate our downloader
    downloader.run(params[1])  # run our downloader
    return params  # job finished, return the same params for identification

if __name__ == "__main__":  # important protection for cross-platform use

    downloader_params = [  # Downloaders will be initialized using these params
        {"port_number": 7751},
        {"port_number": 7851},
        {"port_number": 7951}
    ]
    downloader_cycle = cycle(downloader_params)  # use a cycle for round-robin distribution

    with open("downloaded_links.dat", "a+") as diff_file:  # open your diff file
        diff_file.seek(0)  # rewind the diff file to the beginning to capture all lines
        diff_links = {row.strip() for row in diff_file}  # load downloaded links into a set
        with open("input_links.dat", "r+") as input_file:  # open your input file
            available_links = []
            download_jobs = []  # store our downloader parameters + a link here
            # read our file line by line and filter out downloaded links
            for row in input_file:  # loop through our file
                link = row.strip()  # remove the extra whitespace to get the link
                if link not in diff_links:  # make sure link is not already downloaded
                    available_links.append(row)
                    download_jobs.append([next(downloader_cycle), link])
            input_file.seek(0)  # rewind our input file
            input_file.truncate()  # clear out the input file
            input_file.writelines(available_links)  # store back the available links
            diff_file.seek(0)  # rewind the diff file
            diff_file.truncate()  # blank out the diff file now that the input is updated
        # and now let's get to business...
        if download_jobs:
            download_pool = Pool(processes=5)  # make our pool use 5 processes
            # run asynchronously so we can capture results as soon as they ar available
            for response in download_pool.imap_unordered(init_downloader, download_jobs):
                # since it returns the same parameters, the second item is a link
                # add the link to our `diff` file so it doesn't get downloaded again
                diff_file.write(response[1] + "\n")
        else:
            print("Nothing left to download...")
 
The whole idea is, as I wrote in the comment, to use a file to store downloaded links as they get downloaded, and then on the next run to filter out the downloaded links and update the input file. That way even if you forcibly kill it, it will always resume where it left off (except for the partial downloads).