Add an authorization middleware that supports ACL, RBAC based on casbin.

[xqbumu]

Add an authorization plugin that supports ACL, RBAC based on casbin.

It requires the built-in HTTP basic authentication by default, so the authz can get the user name and enforce the access control.

Test is also added in authz_test.go.

This PR is to solve: #931

[coveralls]

Coverage decreased (-0.08%) to 83.858% when pulling 3a6c9db on xqbumu:middleware-authz into 3359eae on labstack:master.

[coveralls]

Coverage increased (+0.1%) to 84.042% when pulling 43e804d on xqbumu:middleware-authz into 3359eae on labstack:master.

[coveralls]

Coverage increased (+0.1%) to 84.042% when pulling 0bbe2ad on xqbumu:middleware-authz into 3359eae on labstack:master.

[vishr]

@xqbumu I appreciate your contribution to the project. The only concern is external dependencies and this was one of the reason I moved cookbook examples to labstack/echox. We can definitely work through this and find a home for it. Can you provide me casbin's external deps?

[hsluoyz]

Hi @vishr,

Casbin's external dep is only one: github.com/Knetic/govaluate

See here: https://godoc.org/github.com/casbin/casbin?imports

[vishr]

@xqbumu Thanks for the information. What do you think about renaming the prefix Authz to CasbinAuth? This will make it more clear.

Updated: I will also need some help to update middleware docs https://github.com/labstack/echox/tree/master/website/content/middleware - you can also provide a link to your docs as learn more.

[coveralls]

Coverage increased (+0.1%) to 84.042% when pulling f53a65d on xqbumu:middleware-authz into 3359eae on labstack:master.

[coveralls]

Coverage increased (+0.1%) to 84.042% when pulling 706db07 on xqbumu:middleware-authz into 3359eae on labstack:master.

[coveralls]

Coverage increased (+0.1%) to 84.042% when pulling 274dd39 on xqbumu:middleware-authz into 466d509 on labstack:master.

[coveralls]

Coverage increased (+0.1%) to 84.042% when pulling 7044914 on xqbumu:middleware-authz into 466d509 on labstack:master.

[coveralls]

Coverage increased (+0.1%) to 84.059% when pulling 7096092 on xqbumu:middleware-authz into 466d509 on labstack:master.

[coveralls]

Coverage increased (+0.1%) to 84.059% when pulling 7096092 on xqbumu:middleware-authz into 466d509 on labstack:master.

[vishr]

@xqbumu Will get it reviewed soon.

[coveralls]

Coverage increased (+0.1%) to 84.042% when pulling 5f6c3e4 on xqbumu:middleware-authz into 466d509 on labstack:master.

[xqbumu]

@vishr thank you

[vishr]

@xqbumu Thanks for your contribution.

[vishr]

@xqbumu I have moved casbin middlware to https://github.com/labstack/echo-contrib/tree/master/casbin. Please review in case if I have missed something.

[hsluoyz]

Hi @vishr , I found that the link you provided (https://github.com/labstack/echo-contrib/tree/master/casbin) is 404 for me:

any possible causes? Thanks.

[vishr]

Try https://github.com/labstack/echo-contrib

[hsluoyz]

It works now, thanks!