Some Feed Could Not fetch with error infomation "fetch error:Unknown/unsupported feed type" when debug it

Tiny Tiny RSS Support
1

Hello! Some feed could not fetch with error infomation “fetch error:Unknown/unsupported feed type” when debug it.
Feed URL：htt ps://navi.cnki.net/knavi/rss/HKXB
It could be fetched successfully using other rss read app like “Plenary”. And other feeds runs well on my tiny tiny.
Before the error happens, there is one log “saving to local cache: cache/feeds/23f0237fa2fa5ecc205235eb7498830d12470baa.xml”, this file only has these information: . I don’t know if it cause the error.
Thanks so much for reading and help.

  • Tiny Tiny RSS version (including git commit id): I use the synology NAS (DSM 7.1) to fetch feeds, the package is from SynoCommunity and version shows : 20210902-15
  • Platform (i.e. Linux distro, Docker, PHP, PostgreSQL, etc) versions: synology NAS, Linux System

Debug logs is as follows
[15:28:36/3135] start
[15:28:36/3135] setting basic feed info for 16…
[15:28:36/3135] running HOOK_FETCH_FEED handlers…
[15:28:36/3135] feed data has not been modified by a plugin.
[15:28:36/3135] local cache will not be used for this feed
[15:28:36/3135] last unconditional update request: 2022-12-17 15:22:52
[15:28:36/3135] stored last modified for conditional request:
[15:28:36/3135] fetching 航空学报-CNKI (force_refetch: )…
[15:28:36/3135] fetch done.
[15:28:36/3135] effective URL (after redirects): 航空学报-CNKI (IP: 203.81.18.61)
[15:28:36/3135] server last modified:
[15:28:36/3135] saving to local cache: cache/feeds/23f0237fa2fa5ecc205235eb7498830d12470baa.xml
[15:28:36/3135] running HOOK_FEED_FETCHED handlers…
[15:28:36/3135] feed data has not been modified by a plugin.
[15:28:36/3135] fetch error: Unknown/unsupported feed type
[15:28:37/3135] update failed.

2

start here.

even if it is a tt-rss problem (which is unlikely) i’m not going to help you with an unsupported third party package from 2021.

4

Thanks a lot for the link to test the feed. I just test it “航空学报-CNKI”, it shows the same error. is this kind of feed not supported by tt-rss?

5

If nothing else the site is doing User-Agent checking, and unless I masquerade as latest Windows Firefox (rather than default) curl and wget just get a javscript redirect to the front page. With the masquerade it retrieves what looks like, at first glance, a valid feed.

6

Clicking on OP’s provided link in the Brave browser opens to a readable site with links. I.e., html formatted. That shouldn’t happen. If the link was a valid/supported feed link the browser, Brave, (without the aid of an added extension) should open the link as xml text.

The ‘myfeedsucks’ tester reports:

Fetch error: N/A
Error: Unknown/unsupported feed type

So, no mystery here. That link is NOT in rss feed format, thus the error in tt-rss is to be expected.
.

7

Yes, the site is playing silly buggers.

But curl --user-agent "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:108.0) Gecko/20100101 Firefox/108.0" https://navi.cnki.net/knavi/rss/HKXB does yield output starting:

<?xml version="1.0" encoding="utf-8"?>
<?xml-stylesheet type='text/xsl' href='../rssfile/rss.xsl'?>
<rss version="2.0">
  <channel>
    <title>航空学报-CNKI</title>
    <link>http%3A%2F%2Fnavi.cnki.net%2Fknavi%2Frss%2FHKXB%3Fnull/journals/HKXB/detail?uniplatform=NZKPT</link>
    <description>航空学报</description>
    <language>zh-cn</language>
    <pubDate>Sat, 17 Dec 2022 21:21:21 GMT</pubDate>
    <generator>航空学报</generator>
    <image>
      <title>航空学报-CNKI</title>
      <url>https://c61.cnki.net/CJFD/big/HKXB.jpg</url>
      <link>http%3A%2F%2Fnavi.cnki.net%2Fknavi%2Frss%2FHKXB%3Fnull/journals/HKXB/detail?uniplatform=NZKPT</link>
      <width>120</width>
      <height>166</height>
    </image>
    <item>
      <title>基于改进L-SHADE算法的航空发动机性能退化评估</title>
      <link>https://kns.cnki.net/kcms2/article/abstract?v=yIk6Gql3MLeXdVYEumBJYya5zHyN_CvPAhLR5thCvV7vrVCbs3pyL9cvloJNKzwjAvuZkLWWqwLildXPEeh4RJJAxFJ6LRsO5h_yb8vd6x01xBSWWcZxLg==</link>
      <description>秦海勤;赵杰;任立坤;李边疆;&lt;/br&gt;针对航空发动机健康因子求解寻优精度差的问题，提出了一种基于改进L-SHADE算法的航空发动机性能退化评估方法。
首先，采用多工作点分析方法拓展发动机健康因子估计的适应度函数，解决气路测量传感器数量不足的问题；其次，通过引入非线性种群缩减策略解决种群快速缩减的问题；同时通过改进的优化加权变异策略，改变不同迭代阶段贪婪算子的权值，增加了算法的全局搜索和局部开发能力；最后，在30个经典基准函数上验证了改进...</description>
      <pubDate>Thu, 15 Dec 2022 16:00:00 GMT</pubDate>
      <guid>https://kns.cnki.net/kcms2/article/abstract?v=yIk6Gql3MLeXdVYEumBJYya5zHyN_CvPAhLR5thCvV7vrVCbs3pyL9cvloJNKzwjAvuZkLWWqwLildXPEeh4RJJAxFJ6LRsO5h_yb8vd6x01xBSWWcZxLg==</guid>
    </item>

With Firefox, checking via developer tools > network, it’s very definitely returning application/xml content. Perhaps that <?xml-stylesheet type='text/xsl' href='../rssfile/rss.xsl'?> has something to do with the HTML-like rendering in browsers ?

8

LOL, yeah it does profess to be xml doesn’t it? I should have checked the page source, but didn’t.

Anyway, still NOT a tt-rss issue, imo. OP should contact the site’s admin at navi_cnki_net to request a fix/re-write/whatever…
.

9

Yes, I also doubt about that, but I don’t know how to fix it, I’m thinking if I could re-edit it and create a new feed on my server, but I don’t know how to do that. Or should I try any other methods?

10

At first, I also doubt about the feed format, then I try another rss fetch/read app(“Plenary”), it fetched successfully. So I think maybe this site use some kind of new feed type not supported by tt-rss yet?

11

your site is doing redirects based on user agent or something else of this nature. it allows ‘Plenary’ in but redirects tt-rss somewhere else.

12

Thanks for your help and enlighten, finally I found a way to fix it by fetching the cache through phantomjs and then transfer to rss format. It works. :grin: