Adding "preserve_host" flag to APIs, closes Kong#444

Former-commit-id: f97f9385bc5effa6d92be5f4279f5b7cd7f9e8d4

database/migrations/cassandra/2015-08-21-813213_0.5.0.lua

@@ -0,0 +1,17 @@
+local Migration = {
+  name = "2015-08-21-813213_0.5.0",
+
+  up = function(options)
+    return [[
+      ALTER TABLE apis ADD preserve_host boolean;
+    ]]
+  end,
+
+  down = function(options)
+    return [[
+      ALTER TABLE apis DROP preserve_host;
+    ]]
+  end
+}
+
+return Migration

kong.yml

@@ -138,7 +138,8 @@ nginx: |
       location / {
         default_type 'text/plain';
 
-        # This property will be used later by proxy_pass
+        # These properties will be used later by proxy_pass
+        set $backend_host nil;
         set $backend_url nil;
 
         # Authenticate the user and load the API info
@@ -148,6 +149,7 @@ nginx: |
         proxy_set_header X-Real-IP $remote_addr;
         proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
         proxy_set_header X-Forwarded-Proto $scheme;
+        proxy_set_header Host $backend_host;
         proxy_pass $backend_url;
         proxy_pass_header Server;
 

kong/dao/schemas/apis.lua

@@ -83,6 +83,7 @@ return {
                   regex = "([a-zA-Z0-9-]+(\\.[a-zA-Z0-9-]+)*)" },
     path = { type = "string", unique = true, func = check_path },
     strip_path = { type = "boolean" },
-    target_url = { type = "string", required = true, func = validate_target_url }
+    target_url = { type = "string", required = true, func = validate_target_url },
+    preserve_host = { type = "boolean" }
   }
 }

kong/resolver/access.lua

@@ -176,8 +176,12 @@ function _M.execute(conf)
 
   -- Setting the backend URL for the proxy_pass directive
   ngx.var.backend_url = get_backend_url(api)..request_uri
-  ngx.req.set_header("Host", get_host_from_url(ngx.var.backend_url))
-
+  if api.preserve_host then
+    ngx.var.backend_host = ngx.req.get_headers()["host"]
+  else
+    ngx.var.backend_host = get_host_from_url(ngx.var.backend_url)  
+  end
+
   ngx.ctx.api = api
 end
 

spec/integration/proxy/api_resolver_spec.lua

@@ -9,6 +9,7 @@ local http_client = require "kong.tools.http_client"
 
 local STUB_GET_URL = spec_helper.STUB_GET_URL
 local STUB_GET_SSL_URL = spec_helper.STUB_GET_SSL_URL
+local PROXY_URL = spec_helper.PROXY_URL
 
 -- Parses an SSL certificate returned by LuaSec
 local function parse_cert(cert)
@@ -32,7 +33,9 @@ describe("Resolver", function()
         {name = "tests stripped path resolver with pattern characters", target_url = "http://mockbin.com", path = "/mockbin-with-pattern/", strip_path = true},
         {name = "tests deep path resolver", target_url = "http://mockbin.com", path = "/deep/path/", strip_path = true},
         {name = "tests wildcard subdomain", target_url = "http://mockbin.com/status/200", public_dns = "*.wildcard.com"},
-        {name = "tests wildcard subdomain 2", target_url = "http://mockbin.com/status/201", public_dns = "wildcard.*"}
+        {name = "tests wildcard subdomain 2", target_url = "http://mockbin.com/status/201", public_dns = "wildcard.*"},
+        {name = "tests preserve host", public_dns = "httpbin-nopreserve.com", target_url = "http://httpbin.org"},
+        {name = "tests preserve host 2", public_dns = "httpbin-preserve.com", target_url = "http://httpbin.org", preserve_host = true}
       },
       plugin_configuration = {
         { name = "keyauth", value = {key_names = {"apikey"} }, __api = 2 }
@@ -192,4 +195,22 @@ describe("Resolver", function()
     end)
 
   end)
+
+  describe("Preseve Host", function()
+
+    it("should not preserve the host (default behavior)", function()
+      local response, status = http_client.get(PROXY_URL.."/get", nil, { host = "httpbin-nopreserve.com"})
+      assert.equal(200, status)
+      local parsed_response = cjson.decode(response)
+      assert.equal("httpbin.org", parsed_response.headers["Host"])
+    end)
+
+    it("should preserve the host (default behavior)", function()
+      local response, status = http_client.get(PROXY_URL.."/get", nil, { host = "httpbin-preserve.com"})
+      assert.equal(200, status)
+      local parsed_response = cjson.decode(response)
+      assert.equal("httpbin-preserve.com", parsed_response.headers["Host"])
+    end)
+
+  end)
 end)