Add registry validator test; make 404 responses compatible with npm API

[bajtos]

The previous pull request #56 made the 404 response for unknown
package name correct, but broke the expected format of the 404 response
for unknown package version.

This pull request fixes the problem.

The first commit adds a test suite executing npm commands agains the Sinopia registry.

The second commit implements the necessary changes in Sinopia.

[rlidwka]

How about reverting that entire patch?

Sinopia returns a nice error message that depend on an exact error that occured. In the future it might contain information about whether npm registry is reachable or not, or useful other info. Instead of that npm is returning its own error message losing this information.

Also, we're using sinopia behind nginx redirecting https://dev.local/sinopia/ to http://localhost:4873/, and I just found another issue with this:

[alex@dev tmp]$ npm install qwertyueioasvghyujww
npm http GET https://dev.local/sinopia/qwertyueioasvghyujww
npm http 404 https://dev.local/sinopia/qwertyueioasvghyujww
npm ERR! 404 'sinopia' is not in the npm registry.
npm ERR! 404 You should bug the author to publish it
npm ERR! 404 
npm ERR! 404 Note that you can also install from a
npm ERR! 404 tarball, folder, or http url, or git url.

npm ERR! System Linux 2.6.32-431.el6.x86_64
npm ERR! command "node" "/usr/bin/npm" "install" "qwertyueioasvghyujww"
npm ERR! cwd /tmp
npm ERR! node -v v0.10.26
npm ERR! npm -v 1.3.6
npm ERR! code E404
npm ERR! 
npm ERR! Additional logging details can be found in:
npm ERR!     /tmp/npm-debug.log
npm ERR! not ok code 0

[bajtos]

Sinopia returns a nice error message that depend on an exact error that occured. In the future it might contain information about whether npm registry is reachable or not, or useful other info. Instead of that npm is returning its own error message losing this information.

What I don't like about this approach is the stack trace printed by npm, which makes the error look scarier than it is. Users should not get stack traces in common situations like when they a mistype package name.

I suppose the right way how to address custom error messages is to put them in reason or perhaps details field of the json response and alter the npm client to include this field in error messages.

Also, we're using sinopia behind nginx redirecting https://dev.local/sinopia/ to http://localhost:4873/, and I just found another issue with this:

npm http 404 https://dev.local/sinopia/qwertyueioasvghyujww
npm ERR! 404 'sinopia' is not in the npm registry.

That's annoying :( However, it's a bug of the npm client and should be fixed there. I'll try to look into this problem next week and submit a pull request with a fix to the npm project.

How about reverting that entire patch?

I hope my explanation above convinced you that reverting the entire patch is not the best solution.

[rlidwka]

Users should not get stack traces in common situations like when they a mistype package name.

If you mistype version or tag, npm will output stack trace. In fact, npm is outputting stack trace almost on any error. Why this one should be any different?

I suppose the right way how to address custom error messages is to put them in reason

npm ignores "reason" and doesn't write it to the user.

If error message have some vital information, it's better to display it to the user even though it's accompanied by a stack trace.

[rlidwka]

I'll just ask this. Which error message is more useful?

$ npm install express
npm http GET https://example.org/express
npm http 404 https://example.org/express
npm ERR! 404 'express' is not in the npm registry.
npm ERR! 404 You should bug the author to publish it
npm ERR! 404 
npm ERR! 404 Note that you can also install from a
npm ERR! 404 tarball, folder, or http url, or git url.

$ npm install express
npm http GET https://example.org/express
npm http 404 https://example.org/express
npm ERR! Error: no such package available: express (npm registry is down)
npm ERR!     at RegClient.<anonymous> (/usr/local/lib/node_modules/npm/node_modules/npm-registry-client/lib/request.js:272:14)
npm ERR!     at Request.self.callback (/usr/local/lib/node_modules/npm/node_modules/request/request.js:129:22)
npm ERR!     at Request.EventEmitter.emit (events.js:98:17)
npm ERR!     at Request.<anonymous> (/usr/local/lib/node_modules/npm/node_modules/request/request.js:873:14)
npm ERR!     at Request.EventEmitter.emit (events.js:117:20)
npm ERR!     at IncomingMessage.<anonymous> (/usr/local/lib/node_modules/npm/node_modules/request/request.js:824:12)
npm ERR!     at IncomingMessage.EventEmitter.emit (events.js:117:20)
npm ERR!     at _stream_readable.js:920:16
npm ERR!     at process._tickCallback (node.js:415:13)

[bajtos]

Users should not get stack traces in common situations like when they a mistype package name.

If you mistype version or tag, npm will output stack trace. In fact, npm is outputting stack trace almost on any error. Why this one should be any different?

$ npm -v
1.4.6
$ npm --registry=https://registry.npmjs.org/ install not-found
npm http GET https://registry.npmjs.org/not-found
npm http 404 https://registry.npmjs.org/not-found
npm ERR! 404 'not-found' is not in the npm registry.
npm ERR! 404 You should bug the author to publish it
npm ERR! 404
npm ERR! 404 Note that you can also install from a
npm ERR! 404 tarball, folder, or http url, or git url.

[cut: os, node, npm version]
$ npm --registry=https://registry.npmjs.org/ install debug@20.0.0
npm http GET https://registry.npmjs.org/debug/20.0.0
npm http 404 https://registry.npmjs.org/debug/20.0.0
npm ERR! Error: version not found: 20.0.0 : debug/20.0.0
npm ERR!     at RegClient.<anonymous> (/usr/local/lib/node_modules/npm/node_modules/npm-registry-client/lib/request.js:254:14)
npm ERR!     at Request._callback (/usr/local/lib/node_modules/npm/node_modules/npm-registry-client/lib/request.js:192:65)
npm ERR!     at Request.self.callback (/usr/local/lib/node_modules/npm/node_modules/request/request.js:123:22)
npm ERR!     at Request.EventEmitter.emit (events.js:98:17)
npm ERR!     at Request.<anonymous> (/usr/local/lib/node_modules/npm/node_modules/request/request.js:893:14)
npm ERR!     at Request.EventEmitter.emit (events.js:117:20)
npm ERR!     at IncomingMessage.<anonymous> (/usr/local/lib/node_modules/npm/node_modules/request/request.js:844:12)
npm ERR!     at IncomingMessage.EventEmitter.emit (events.js:117:20)
npm ERR!     at _stream_readable.js:920:16
npm ERR!     at process._tickCallback (node.js:415:13)
npm ERR! If you need help, you may report this *entire* log,
npm ERR! including the npm and node versions, at:
npm ERR!     <http://github.com/npm/npm/issues>

[cut: os, node, npm version]

I wanted to write that you are not right, but alas, it's really printing stack traces :(

In that case you are probably right, let's revert #56 and close this one. I'll try to figure out how to fix my test suite to make the error message check less strict.

[bajtos]

BTW, when the package is not found because the public registry is down, you should probably return 504 Gateway Timeout instead of 404.

The server, while acting as a gateway or proxy, did not receive a timely response from the upstream server specified by the URI (e.g. HTTP, FTP, LDAP) or some other auxiliary server (e.g. DNS) it needed to access in attempting to complete the request.