下载有些资源失败，http 412错误

[zhouxiongjie]

Connection failed with request[{If-Match=[W/"5dea0200-bd41"], Range=[bytes=0-], User-Agent=[FileDownloader/1.7.7]}] response[{null=[HTTP/1.1 412 Precondition Failed], Connection=[keep-alive], Content-Length=[195], Content-Type=[text/html; charset=utf-8], Date=[Fri, 06 Dec 2019 08:53:35 GMT], Server=[openresty/1.13.6.1], X-Android-Received-Millis=[1575622415051], X-Android-Response-Source=[NETWORK 412], X-Android-Selected-Protocol=[http/1.1], X-Android-Sent-Millis=[1575622415014]}] http-state[412] on task[-1974179381--1], which is changed after verify connection, so please try again. 这是输出错误

[rantianhua]

可能因为是服务对对弱值 Etag 支持有问题，参照 #1066 ，将 etag 改为强值试试。

[Doraemon123]

error: Connection failed with request[{If-Match=["81405-5a231e6c9d912-gzip"], Range=[bytes=0-], User-Agent=[FileDownloader/1.7.4]}] response[{null=[HTTP/1.1 412 Precondition Failed], Accept-Ranges=[bytes], Connection=[Upgrade, Keep-Alive], Content-Length=[0], Content-Type=[application/vnd.openxmlformats-officedocument.presentationml.presentation], Date=[Wed, 08 Apr 2020 03:11:13 GMT], ETag=["81405-5a231e6c9d912"], Keep-Alive=[timeout=60, max=1000], Last-Modified=[Wed, 01 Apr 2020 03:01:32 GMT], Server=[Apache], Upgrade=[h2], X-Android-Received-Millis=[1586315470213], X-Android-Response-Source=[NETWORK 412], X-Android-Selected-Protocol=[http/1.1], X-Android-Sent-Millis=[1586315470177]}] http-state[412] on task[262543029--1], which is changed after verify connection, so please try again. 出现同样问题 但看着不是弱Etag

[kayesn786]

@rantianhua getting this error while downloading concurrent files.

request headers: {Range=[bytes=0-0], User-Agent=[FileDownloader/1.7.7]} response headers: {null=[HTTP/1.1 403 Forbidden], Alt-Svc=[h3-27=":443"; ma=2592000,h3-25=":443"; ma=2592000,h3-T050=":443"; ma=2592000,h3-Q050=":443"; ma=2592000,h3-Q046=":443"; ma=2592000,h3-Q043=":443"; ma=2592000,quic=":443"; ma=2592000; v="46,43"], Content-Length=[1103], Content-Type=[text/html; charset=UTF-8], Date=[Tue, 30 Jun 2020 15:10:23 GMT], X-Android-Received-Millis=[1593529823253], X-Android-Response-Source=[NETWORK 403], X-Android-Selected-Protocol=[http/1.1], X-Android-Sent-Millis=[1593529817185]}

[yxwzaxns]

Connection failed with request[{If-Match=["5e75b72e-3cb6"], Range=[bytes=0-], User-Agent=[FileDownloader/1.7.5]}] response[{null=[HTTP/1.1 412 Precondition Failed], Access-Control-Allow-Methods=[GET,POST,OPTIONS,HEAD], Access-Control-Allow-Origin=[*], Access-Control-Expose-Headers=[Authorization,Origin,X-Requested-With,Content-Type,Accept], Connection=[keep-alive], Content-Length=[0], Content-Type=[text/html], Date=[Mon, 13 Jul 2020 14:23:47 GMT], Location=[xxxxx], Server=[nginx], X-Android-Received-Millis=[1594650229263], X-Android-Response-Source=[NETWORK 412], X-Android-Selected-Protocol=[http/1.1], X-Android-Sent-Millis=[1594650229247], X-Via-Ucdn=[MISS by x.x.x.x, MISS by x.x.x.x]}] http-state[412] on task[-903433104--1], which is changed after verify connection, so please try again

[hayukleung]

Connection failed with request[{If-Match=[W/"5f0ffe38-55769c8"], Range=[bytes=0-], User-Agent=[FileDownloader/0.0.1]}] response[{null=[HTTP/1.1 412 Precondition Failed], Connection=[keep-alive], Content-Length=[173], Content-Type=[text/html], Date=[Thu, 16 Jul 2020 09:24:13 GMT], Server=[nginx/1.16.1], X-Android-Received-Millis=[1594891453354], X-Android-Response-Source=[NETWORK 412], X-Android-Selected-Protocol=[http/1.1], X-Android-Sent-Millis=[1594891453116]}] http-state[412] on task[-1296041228--1], which is changed after verify connection, so please try again.

[qyzhaojinxi]

有同样问题

"Connection failed with request[{Connection=[close], If-Match=[9eca7026d6a3253cb2e2d1c77f25c1cf], p=[L3TkhLK5TBFxc4Drgd5uL4nziXFugwUweahpR9V4bT3wf7W0iPF6NZVmkZ9BMUO7QYm8Tf1wbF9miN0=], Range=[bytes=88914262-89566183], s=[c5655481855a1fcd4605cfa9129dd924], User-Agent=[FileDownloader/1.0.1], v=[b11fe760be080b353c584e5144c9147a]}] response[{null=[HTTP/1.1 412 Precondition Failed], Age=[597609], CF-Cache-Status=[HIT], CF-RAY=[6029af72aad21ec2-AMS], cf-request-id=[070debfba800001ec2d8b7b000000001], Connection=[close], Content-Type=[text/html], Date=[Wed, 16 Dec 2020 16:12:20 GMT], NEL=[{"report_to":"cf-nel","max_age":604800}], Report-To=[{"endpoints":[{"url":"https:\/\/a.nel.cloudflare.com\/report?s=AyxXi5BNqas7sQT9NJjEA27pZIx0bM%2BFlsTNSePAORHBVIiJPIFX44oGedcmL236i%2FvdeDKg8lwgLLtLo1%2B1MwcscOx3RBw%2F8cXJK1P0XQtvoQi9sjBq68Himw0dQf9TNA%3D%3D"}],"group":"cf-nel","max_age":604800}], Server=[cloudflare], Set-Cookie=[__cfduid=d2f7a4524a32b7723fc484f90732ccdea1608135140; expires=Fri, 15-Jan-21

[Seachal]

对我来说， 第一个版本服务端没有对文件下载进行鉴权限制，可以正常下载，第二个版本，服务端开始改造增加鉴权，对已经调用过一次的下载链接进行失效处理，我这边就会遇到下面这样的异常，

ava.net.SocketException: Connection failed with request[{Range=[bytes=4073926-8147851], User-Agent=[FileDownloader/1.7.7]}] response[{null=[HTTP/1.1 403 Forbidden], Access-Control-Allow-Methods=[GET], Access-Control-Allow-Origin=[*], Connection=[keep-alive], Content-Length=[238], Content-Type=[text/html], Date=[Mon, 29 Jan 2024 02:42:16 GMT], EagleId=[907b1f2217064961368347077e], Server=[Tengine], Timing-Allow-Origin=[*], Via=[cache14.cn1306[,0]], X-Android-Received-Millis=[1706496136376], X-Android-Response-Source=[NETWORK 403], X-Android-Selected-Protocol=[http/1.1], X-Android-Sent-Millis=[1706496136196]}] http-state[403] on task[-891346639-1], which is changed after verify connection, so please try again.   

最终发现是因为 下载库默认开启断点续传。

Range 是一个请求首部，告知服务器返回文件的哪一部分。在一个 Range 首部中，可以一次性请求多个部分，服务器会以 multipart 文件的形式将其返回。如果服务器返回的是范围响应，需要使用 206 Partial Content 状态码。假如所请求的范围不合法，那么服务器会返回 416 Range Not Satisfiable 状态码，表示客户端错误。服务器允许忽略 Range 首部，从而返回整个文件，状态码用 200 。

所以我这边的情况是，服务端做修改适配客户端的断点续传，客户端不需要修改。