feat(key-auth): supporting key-auth plugin to get key from query string

[wisdom-yzh]

What this PR does / why we need it:

fixes issue #4421

Adding a new query property to key-auth plugin, which can get key value from http query string

Pre-submission checklist:

• Did you explain what problem does this PR solve? Or what new features have been added?
• Have you added corresponding test cases?
• Have you modified the corresponding document?
• Is this PR backward compatible? If it is not backward compatible, please discuss on the mailing list first

[tokers]

@wisdom-yzh From the changes I guess you tried to introduce an using order between the header and query, it will be somewhat obscure, we may treat them equally but set them as exclusive in jsonschema (e.g. by introducing the oneOf primitive).

[wisdom-yzh]

@tokers Accord to description of #4421, I guess @forgaoqiang wants to get key from both query string and headers, not exclusive. Maybe I can define one field instead of two fields, and check key from both query and headers?

[spacewander]

I think "header and query string" is OK, as jwt-auth plugin does it:

apisix/apisix/plugins/jwt-auth.lua

Line 154 in 07bfe5b

local function fetch_jwt_token(ctx)

[spacewander]

Please don't add the test in the middle of the other test. And we need to verify it via GET /hello?xxx in its own version of "valid consumer"

[wisdom-yzh]

@spacewander hi~I have changed strategy to "header and query string", and then rename field from "header" to "key_name“.

[spacewander]

@wisdom-yzh
Err... We can't change the existing fields which will break the user's configuration. Your original solution is good enough, please bring it back.

[wisdom-yzh]

@wisdom-yzh
Err... We can't change the existing fields which will break the user's configuration. Your original solution is good enough, please bring it back.

ok, i'll restore the origin commit and fix the test case issue soon

[forgaoqiang]

Great, this feature is what I needed, thanks