通过XHR请求Reddit托管的视频的HLS/破折号URL会导致“CORS头”访问-控制-允许-原产地‘缺失“错误
我正在尝试使用hls.js库显示Reddit托管的HLS/DASH播放列表中的视频。但是，通过XHR访问任何Reddit HLS/DASH url (例如这一个 )都将失败，因为错误说的是相同的原产地策略违规：
Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at https://v.redd.it/5r0nz8sywgl41/DASHPlaylist.mpd. (Reason: CORS header ‘Access-Control-Allow-Origin’ missing).
奇怪的是，请求优先获取是一个选项，它确实返回访问控制-允许-原产地标头与正确的源url。我可以在开发人员控制台中看到响应，但是请求仍然“失败”。如果我使用“允许CORS:访问-控制-允许-起源”扩展，一切都可以正常工作。，我做错了什么？
选项请求头：
Host: v.redd.it
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:73.0) Gecko/20100101 Firefox/73.0
Accept: */*
Accept-Language: lt,en-US;q=0.7,en;q=0.3
Accept-Encoding: gzip, deflate, br
Access-Control-Request-Method: GET
Access-Control-Request-Headers: authorization
Referer: http://localhost:3000/
Origin: http://localhost:3000
DNT: 1
Connection: keep-alive
Save-Data: on
Pragma: no-cache
Cache-Control: no-cache
TE: Trailers选项响应头：
HTTP/2 200 OK
retry-after: 0
access-control-allow-origin: http://localhost:3000
access-control-allow-headers: authorization
access-control-allow-methods: GET
access-control-max-age: 3000
date: Sun, 08 Mar 2020 18:40:29 GMT
via: 1.1 varnish
x-served-by: cache-hhn4029-HHN
x-cache: HIT
x-cache-hits: 0
x-timer: S1583692829.044409,VS0,VE0
server: snooserv
accept-ranges: bytes
x-cdn-server-region: EU-East
x-cdn-client-region: EU
x-cdn-name: fastly
access-control-expose-headers: x-cdn-server-region, x-cdn-client-region, x-cdn-name
cache-control: public, max-age=604800, s-maxage=86400, must-revalidate
vary: Access-Control-Request-Headers, Access-Control-Request-Method,Origin
content-length: 0
X-Firefox-Spdy: h2获取请求头：
Host: v.redd.it
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:73.0) Gecko/20100101 Firefox/73.0
Accept: */*
Accept-Language: lt,en-US;q=0.7,en;q=0.3
Accept-Encoding: gzip, deflate, br
Referer: http://localhost:3000/
Authorization: Bearer --------------------------- (actual token here)
Origin: http://localhost:3000
DNT: 1
Connection: keep-alive
Save-Data: on
Pragma: no-cache
Cache-Control: no-cache
TE: Trailers获取响应头：
HTTP/2 200 OK
last-modified: Sun, 08 Mar 2020 15:34:11 GMT
etag: "0abfb243cb8d03188bf34ff29d6d4af8"
content-type: application/dash+xml
via: 1.1 varnish
date: Sun, 08 Mar 2020 18:40:29 GMT
via: 1.1 varnish
x-served-by: cache-bwi5138-BWI, cache-hhn4029-HHN
x-cache: HIT, HIT
x-cache-hits: 2, 34
x-timer: S1583692829.127808,VS0,VE0
server: snooserv
accept-ranges: bytes
x-cdn-server-region: EU-East
x-cdn-client-region: EU
x-cdn-name: fastly
access-control-expose-headers: x-cdn-server-region, x-cdn-client-region, x-cdn-name
cache-control: public, max-age=604800, s-maxage=86400, must-revalidate
vary: Origin
content-length: 1976
X-Firefox-Spdy: h2得到回应：
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<MPD mediaPresentationDuration="PT15.034S" minBufferTime="PT1.500S" profiles="urn:mpeg:dash:profile:isoff-on-demand:2011" type="static" xmlns="urn:mpeg:dash:schema:mpd:2011">
<Period duration="PT15.034S">
<AdaptationSet segmentAlignment="true" subsegmentAlignment="true" subsegmentStartsWithSAP="1">
<Representation bandwidth="1172841" codecs="avc1.4d401f" frameRate="30" height="480" id="VIDEO-1" mimeType="video/mp4" startWithSAP="1" width="720">
<BaseURL>DASH_480</BaseURL>
<SegmentBase indexRange="913-992" indexRangeExact="true">
<Initialization range="0-912"/>
</SegmentBase>
</Representation>
<Representation bandwidth="784684" codecs="avc1.4d401e" frameRate="30" height="360" id="VIDEO-2" mimeType="video/mp4" startWithSAP="1" width="540">
<BaseURL>DASH_360</BaseURL>
<SegmentBase indexRange="915-994" indexRangeExact="true">
<Initialization range="0-914"/>
</SegmentBase>
</Representation>
<Representation bandwidth="592784" codecs="avc1.4d401e" frameRate="30" height="240" id="VIDEO-3" mimeType="video/mp4" startWithSAP="1" width="360">
<BaseURL>DASH_240</BaseURL>
<SegmentBase indexRange="915-994" indexRangeExact="true">
<Initialization range="0-914"/>
</SegmentBase>
</Representation>
<Representation bandwidth="91690" codecs="avc1.4d400a" frameRate="30" height="96" id="VIDEO-4" mimeType="video/mp4" startWithSAP="1" width="144">
<BaseURL>DASH_96</BaseURL>
<SegmentBase indexRange="912-991" indexRangeExact="true">
<Initialization range="0-911"/>
</SegmentBase>
</Representation>
</AdaptationSet>
</Period>
</MPD>非常感谢你的帮助。
回答 1
Stack Overflow用户
发布于 2020-03-09 11:05:16
问题只是:从https://v.redd.it/5r0nz8sywgl41/DASHPlaylist.mpd到代码中的GET请求的响应不包括Access-Control-Allow-Origin响应头。奇怪的是，它确实包含了Access-Control-Expose-Headers响应头。因此，原因只是服务器配置错误，实际上没有正确启用CORS。
具体而言:即使服务器发送一个Access-Control-Allow-Origin头来响应OPTIONS预飞，但这本身并不足以使浏览器允许您的前端代码访问代码中实际GET请求的响应。要使代码工作，服务器还必须发送Access-Control-Allow-Origin头，以响应该GET请求。
但是，您实际上可以绕过https://v.redd.it错误配置，从您的前端代码访问Reddit HLS/破折号URL，而不需要浏览器扩展--通过CORS代理发出请求，如下面的示例所示。
const proxyurl = "https://cors-anywhere.herokuapp.com/";
const url = "https://v.redd.it/5r0nz8sywgl41/DASHPlaylist.mpd";
fetch(proxyurl + url)
.then(response => response.text())
.then(contents => console.log(contents))
有关解释，请参见https://stackoverflow.com/a/43881141/441757的答案。
您可以使用来自https://github.com/Rob--W/cors-anywhere/的代码轻松地运行您自己的代理，并且您可以使用5个命令在2到3分钟内将您自己的代理快速部署到Heroku：
git clone https://github.com/Rob--W/cors-anywhere.git
cd cors-anywhere/
npm install
heroku create
git push heroku master运行这些命令之后，您将得到您自己的CORS Anywhere服务器，例如在https://cryptic-headland-94862.herokuapp.com/上运行。因此，与其用https://cors-anywhere.herokuapp.com作为请求URL的前缀，不如为您自己的实例添加URL前缀；例如，https://cryptic-headland-94862.herokuapp.com/https://example.com。
https://stackoverflow.com/questions/60591030
复制相似问题
腾讯云开发者
