实时抓取已标记的instagram照片 [英] Grabbing tagged instagram photos in real time

问题描述

我正在尝试实时下载带有特定标签的照片.我发现实时api几乎没有用，所以我在使用长轮询策略.下面是伪代码，其中注释了一些错误

I'm trying to download photos posted with specific tag in real time. I found real time api pretty useless so I'm using long polling strategy. Below is pseudocode with comments of sublte bugs in it

newMediaCount = getMediaCount();
delta = newMediaCount - mediaCount;
if (delta > 0) {
    // if mediaCount changed by now, realDelta > delta, so realDelta - delta photos won't be grabbed and on next poll if mediaCount didn't change again realDelta - delta would be duplicated else ...
    // if photo posted from private account last photo will be duplicated as counter changes but nothing is added to recent
    recentMedia = getRecentMedia(delta);
    // persist recentMedia
    mediaCount = newMediaCount;
}

第二个问题可以通过我猜过的Set解决.但是首先真的困扰我.我已将两个呼叫移至instagram api的距离尽可能近，但这够了吗?

Second issue can be addressed with Set of some sort I gueess. But first really bothers me. I've moved two calls to instagram api as close as possible but is this enough?

修改

正如Amir所建议的那样，我已经使用min/max_tag_id s重写了代码.但它仍会跳过照片.除了将图像保存在磁盘上一段时间并将结果与​​instagram.com/explore/tags/进行比较之外，我找不到更好的测试方法.

As Amir suggested I've rewritten the code with use of min/max_tag_ids. But it still skips photos. I couldn't find better way to test this than save images on disk for some time and compare result to instagram.com/explore/tags/.

public class LousyInstagramApiTest {

   @Test
    public void testFeedContinuity() throws Exception {
        Instagram instagram = new Instagram(Settings.getClientId());
        final String TAG_NAME = "portrait";
        String id = instagram.getRecentMediaTags(TAG_NAME).getPagination().getMinTagId();
        HashtagEndpoint endpoint = new HashtagEndpoint(instagram, TAG_NAME, id);

        for (int i = 0; i < 10; i++) {
            Thread.sleep(3000);
            endpoint.recentFeed().forEach(d -> {
                try {
                    URL url = new URL(d.getImages().getLowResolution().getImageUrl());
                    BufferedImage img = ImageIO.read(url);
                    ImageIO.write(img, "png", new File("D:\\tmp\\" + d.getId() + ".png"));
                } catch (Exception e) {
                    e.printStackTrace();
                }
            });
        }
    }
}

class HashtagEndpoint {
    private final Instagram instagram;
    private final String hashtag;
    private String minTagId;

    public HashtagEndpoint(Instagram instagram, String hashtag, String minTagId) {
        this.instagram = instagram;
        this.hashtag = hashtag;
        this.minTagId = minTagId;
    }

    public List<MediaFeedData> recentFeed() throws InstagramException {
        TagMediaFeed feed = instagram.getRecentMediaTags(hashtag, minTagId, null);
        List<MediaFeedData> dataList = feed.getData();
        if (dataList.size() == 0) return Collections.emptyList();

        String maxTagId = feed.getPagination().getNextMaxTagId();
        if (maxTagId != null && maxTagId.compareTo(minTagId) > 0) dataList.addAll(paginateFeed(maxTagId));
        Collections.reverse(dataList);
//        dataList.removeIf(d -> d.getId().compareTo(minTagId) < 0);

        minTagId = feed.getPagination().getMinTagId();
        return dataList;
    }

    private Collection<? extends MediaFeedData> paginateFeed(String maxTagId) throws InstagramException {
        System.out.println("pagination required");

        List<MediaFeedData> dataList = new ArrayList<>();
        do {
            TagMediaFeed feed = instagram.getRecentMediaTags(hashtag, null, maxTagId);
            maxTagId = feed.getPagination().getNextMaxTagId();
            dataList.addAll(feed.getData());
        } while (maxTagId.compareTo(minTagId) > 0);
        return dataList;
    }

}

推荐答案

使用标记端点来获取带有所需标签的最新媒体，它会在其分页信息中返回min_tag_id，该信息会在您致电时与最新标签的媒体绑定在一起.由于API还接受min_tag_id参数，因此您可以从上一次查询传递该数字，以仅接收在上一次查询之后被标记的那些媒体.

Using the Tag endpoints to get the recent media with a desired tag, it returns a min_tag_id in its pagination info, which is tied to the most recently tagged media at the time of your call. As the API also accepts a min_tag_id parameter, you can pass that number from your last query to only receive those media that are tagged after your last query.

因此，基于您拥有的任何轮询机制，您只需调用API即可获取最新的新媒体(如果有的话)是基于上次收到的min_tag_id.

So based on whatever polling mechanism you have, you just call the API to get the new recent media if any based on last received min_tag_id.

当标记速度快于轮询速度时，您还需要传递一个大的count参数并遵循响应的分页以接收所有数据而不会丢失任何数据.

You will also need to pass a large count parameter and follow the pagination of the response to receive all data without losing anything when the speed of tagging is faster than your polling.

更新:
根据您更新的代码:

Update:
Based on your updated code:

public List<MediaFeedData> recentFeed() throws InstagramException {
    TagMediaFeed feed = instagram.getRecentMediaTags(hashtag, minTagId, null, 100000);
    List<MediaFeedData> dataList = feed.getData();
    if (dataList.size() == 0) return Collections.emptyList();

    // follow the pagination
    MediaFeed recentMediaNextPage = instagram.getRecentMediaNextPage(feed.getPagination());
    while (recentMediaNextPage.getPagination() != null) {
        dataList.addAll(recentMediaNextPage.getData());
        recentMediaNextPage = instagram.getRecentMediaNextPage(recentMediaNextPage.getPagination());
    }

    Collections.reverse(dataList);

    minTagId = feed.getPagination().getMinTagId();
    return dataList;
}

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