Fix OSS check

[chinesedfan]

Pull Request Template:

Describe what you did

Fix function is_oss_ok.

• the recursive call should use the whole rest part as an argument
• the awk picks the wrong location with \r at the end

How you did it

Fixed by,

• wrap the rest by backticks
• replace awk with sed

How to verify it doesn't effect the functionality of n

NODE_MIRROR=https://npm.taobao.org/mirrors/node/ n 8.9.0

If this solves an issue, please put issue in PR notes.

• Solved "n project" command failed #314.
• Enable some special mirror #318 tried to fix but failed, and Fixed illegal char error in is_oss_ok function. #460 is not the best way.

If this solves an issue, please include the output of issue that had problems and then the fixed output from the same command.

• Before

[zhong@localhost n]$ NODE_MIRROR=https://npm.taobao.org/mirrors/node/ n 8.9.0

     install : node-v8.9.0

  Error: invalid version 8.9.0

• After (Very quickly in China! But the official nodejs.org is slow due to network censorship.)

[zhong@localhost n]$ NODE_MIRROR=https://npm.taobao.org/mirrors/node/ n 8.9.0

     install : node-v8.9.0
       mkdir : /usr/local/n/versions/node/8.9.0
       fetch : https://npm.taobao.org/mirrors/node/v8.9.0/node-v8.9.0-darwin-x64.tar.gz
######################################################################## 100.0%
   installed : v8.9.0

Squash any unnecessary commits to keep history clean as possible

Only 1 commit.

Place description for the changelog in PR so we can tally all changes for any future release

Fix OSS check then able to download from special mirror sites.

[chinesedfan]

Updated with an optimization that saving headers in a local variable. Now it only needs to send 2 requests to check OSS resources, while the old implementation needs 4 requests.

[shadowspawn]

I agree is_oss_ok was broken, but I am unable to reproduce the failure as described. Is n still failing for you in the same way?

I tried reproducing with MacOS and centos:6.6 and ubuntu:12.04 and ubuntu:latest.

For your interest, I am trying a different approach by changing is_ok, no parsing, no extra requests:

function is_ok() {
  if command -v curl &> /dev/null; then
    ${GET} --fail --head "$1" &> /dev/null || return 1
  else
    ${GET} --spider "$1" &> /dev/null || return 1
  fi
}

[chinesedfan]

@JohnRGee It was several months ago. Maybe something has changed. grep Location will include \r\n and cause the re-fetch throws an error.

Thanks for your is_ok. But can you explain a little more about why it can handle 302 as well?

[shadowspawn]

Redirects:

• CURL_PARAMS includes -L so curl follows redirects
• wget follows up to 20 redirects by default according to this page, see --max-redirect

I checked archlinux and centos and ubuntu and Mac.

Example:

# wget -O- --spider https://npm.taobao.org/mirrors/node/v9.11.0/node-v9.11.0-linux-arm64.tar.gz
...
HTTP request sent, awaiting response... 302 Found
Location: http://cdn.npm.taobao.org/dist/node/v9.11.0/node-v9.11.0-linux-arm64.tar.gz [following]
Spider mode enabled. Check if remote file exists.
--2018-07-21 12:07:49--  http://cdn.npm.taobao.org/dist/node/v9.11.0/node-v9.11.0-linux-arm64.tar.gz
...
HTTP request sent, awaiting response... 200 OK
Length: 17897624 (17M) [application/octet-stream]
Remote file exists.

# curl --head -L https://npm.taobao.org/mirrors/node/v9.11.0/node-v9.11.0-linux-arm64.tar.gz
HTTP/2 302 
...

HTTP/1.1 200 OK
...
Content-Length: 17897624
....

[shadowspawn]

(I am not a maintainer.)

When I tried working through the code I found it does not currently work as intended. The location returned is currently all lowercase.

$ curl -Is -L https://npm.taobao.org/mirrors/node/v10.0.0/node-v10.0.0-darwin-x64.tar.gz | grep ocation
location: http://cdn.npm.taobao.org/dist/node/v10.0.0/node-v10.0.0-darwin-x64.tar.gz

I checked and headers are officially case insensitive, so I suggest the searches are case insensitive too.

https://tools.ietf.org/html/rfc7230#section-3.2

[shadowspawn]

See #560 for open issue. Subscribe to that for updates and/or add 👍 to show interest