Re-target support

[huangningfa]

Need re-target support like Router.

router: {
    'integration.localhost:3000' : 'http://127.0.0.1:8001',  // host only
    'staging.localhost:3000'     : 'http://127.0.0.1:8002',  // host only
    'localhost:3000/api'         : 'http://127.0.0.1:8003',  // host + path
    '/rest'                      : 'http://127.0.0.1:8004'   // path only
}

// Support custom router function (string target)
router: function(req) {
    return 'http://127.0.0.1:8004';
}

In my case, target is depend on proxyReq.host.

[williamstein]

This seems like a cool idea for a feature to add. Any chance you would add it as a PR? I am definitely open to adding it, since it seems natural.

[b40606828-prog]

router: {
    'integration.localhost:3000' : 'http://127.0.0.1:8001',  // host only
    'staging.localhost:3000'     : 'http://127.0.0.1:8002',  // host only
    'localhost:3000/api'         : 'http://127.0.0.1:8003',  // host + path
    '/rest'                      : 'http://127.0.0.1:8004'   // path only
}

// Support custom router function (string target)
router: function(req) {
    return 'http://127.0.0.1:8004';
}

[b40606828-prog]

router: {
    'integration.localhost:3000' : 'http://127.0.0.1:8001',  // host only
    'staging.localhost:3000'     : 'http://127.0.0.1:8002',  // host only
    'localhost:3000/api'         : 'http://127.0.0.1:8003',  // host + path
    '/rest'                      : 'http://127.0.0.1:8004'   // path only
}

// Support custom router function (string target)
router: function(req) {
    return 'http://127.0.0.1:8004';
}