From 667a9d062108e0fd8ab36def092cbfac7afdaf92 Mon Sep 17 00:00:00 2001
From: Eric Marden <eric.marden@gmail.com>
Date: Wed, 15 Mar 2017 15:53:12 -0500
Subject: [PATCH] adds methods to parse params

- currently focuses on `GET` requests (punting on deseralizing bodies
until we have #44 figured out, though `BodyParams` was added as a stand
in)
- param source precedence was implemented, with each subsequent source
overwriting keys in ones proceeding it: `query`,` body`, `path`
- params are parsed into `url.Values`, for consistency. #43 will go
further and cast this into the appropriate types.
- currently, nothing is calling `Params()`, the main entry point for
parsing params from all sources -- this will change as all of the
tickets that implment #3 come together

fixes #41
---
 hyperdrive_test.go |  3 +++
 params.go          | 59 ++++++++++++++++++++++++++++++++++++++++++++++
 params_test.go     | 52 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 114 insertions(+)
 create mode 100644 params.go
 create mode 100644 params_test.go

diff --git a/hyperdrive_test.go b/hyperdrive_test.go
index 1f5415a..7b5392c 100644
--- a/hyperdrive_test.go
+++ b/hyperdrive_test.go
@@ -2,6 +2,7 @@ package hyperdrive
 
 import (
 	"net/http"
+	"net/http/httptest"
 	"testing"
 
 	"github.com/stretchr/testify/suite"
@@ -14,6 +15,7 @@ type HyperdriveTestSuite struct {
 	TestHandler          http.Handler
 	TestRoot             *RootResource
 	TestEndpointResource EndpointResource
+	TestGetRequest       *http.Request
 }
 
 func (suite *HyperdriveTestSuite) SetupTest() {
@@ -22,6 +24,7 @@ func (suite *HyperdriveTestSuite) SetupTest() {
 	suite.TestHandler = NewMethodHandler(suite.TestEndpoint)
 	suite.TestRoot = NewRootResource(suite.TestAPI)
 	suite.TestEndpointResource = NewEndpointResource(suite.TestEndpoint)
+	suite.TestGetRequest = httptest.NewRequest("GET", "/test/2?id=1&a=b", nil)
 }
 
 func (suite *HyperdriveTestSuite) TestNewAPI() {
diff --git a/params.go b/params.go
new file mode 100644
index 0000000..237a767
--- /dev/null
+++ b/params.go
@@ -0,0 +1,59 @@
+package hyperdrive
+
+import (
+	"net/http"
+	"net/url"
+
+	"github.com/gorilla/mux"
+)
+
+// QueryParams extracts the values from the request QueryString. It returns
+// a url.Values object (essentially map[string][]string). If the
+// request method is not GET, an empty url.Values is returned.
+func QueryParams(r *http.Request) url.Values {
+	if r.Method == "GET" {
+		r.ParseForm()
+		return r.Form
+	}
+	return url.Values{}
+}
+
+// BodyParams deserializes the input, and extracts the values from the request
+// body. It returns a url.Values object (essentially map[string][]string). If
+// the request method is GET, an empty url.Values is returned.
+func BodyParams(r *http.Request) url.Values {
+	if r.Method != "GET" {
+		return url.Values{}
+	}
+	return url.Values{}
+}
+
+// PathParams extracts the values from the request path which match named
+// params in the route. They are returned as url.Values for consistincey
+// with http.Request.Form's behaviour.
+func PathParams(r *http.Request) url.Values {
+	var params = url.Values{}
+	for k, v := range mux.Vars(r) {
+		params.Add(k, v)
+	}
+	return params
+}
+
+// Params extracts the param values from all sources: query, body, and path -- in
+// that order. Each subsequent source will overwrite values with the same key, to
+// ensure API client intent is maintained in a consistent way.
+func Params(r *http.Request) url.Values {
+	var params = QueryParams(r)
+
+	for k, values := range BodyParams(r) {
+		for _, v := range values {
+			params.Set(k, v)
+		}
+	}
+
+	for k, v := range mux.Vars(r) {
+		params.Set(k, v)
+	}
+
+	return params
+}
diff --git a/params_test.go b/params_test.go
new file mode 100644
index 0000000..d8fafcf
--- /dev/null
+++ b/params_test.go
@@ -0,0 +1,52 @@
+package hyperdrive
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+)
+
+func (suite *HyperdriveTestSuite) TestQueryParamsGet() {
+	suite.IsType(url.Values{}, QueryParams(suite.TestGetRequest), "expects an instance of url.Values")
+}
+
+func (suite *HyperdriveTestSuite) TestQueryParamsGetValues() {
+	suite.Equal(url.Values{"id": []string{"1"}, "a": []string{"b"}}, QueryParams(suite.TestGetRequest), "returns populated url.Values")
+}
+
+func (suite *HyperdriveTestSuite) TestBodyParamsGet() {
+	suite.IsType(url.Values{}, BodyParams(suite.TestGetRequest), "expects an instance of url.Values")
+}
+
+func (suite *HyperdriveTestSuite) TestBodyParamsGetValues() {
+	suite.Equal(url.Values{}, BodyParams(suite.TestGetRequest), "returns populated url.Values")
+}
+
+func (suite *HyperdriveTestSuite) TestPathParamsGet() {
+	suite.TestAPI.Router.Handle("/test/{id}", http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		suite.IsType(url.Values{}, PathParams(suite.TestGetRequest), "expects an instance of url.Values")
+	}))
+	suite.TestAPI.Router.ServeHTTP(httptest.NewRecorder(), suite.TestGetRequest)
+}
+
+func (suite *HyperdriveTestSuite) TestPathParamsGetValues() {
+	suite.TestAPI.Router.Handle("/test/{id}", http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		suite.Equal(url.Values{"id": []string{"2"}}, PathParams(r), "returns populated url.Values")
+	}))
+	suite.TestAPI.Router.ServeHTTP(httptest.NewRecorder(), suite.TestGetRequest)
+}
+
+func (suite *HyperdriveTestSuite) TestParamsGet() {
+	suite.TestAPI.Router.Handle("/test/{id}", http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		suite.IsType(url.Values{}, Params(suite.TestGetRequest), "expects an instance of url.Values")
+	}))
+	suite.TestAPI.Router.ServeHTTP(httptest.NewRecorder(), suite.TestGetRequest)
+
+}
+
+func (suite *HyperdriveTestSuite) TestParamsGetValues() {
+	suite.TestAPI.Router.Handle("/test/{id}", http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		suite.Equal(url.Values{"id": []string{"1"}, "a": []string{"b"}}, Params(suite.TestGetRequest), "returns populated url.Values")
+	}))
+	suite.TestAPI.Router.ServeHTTP(httptest.NewRecorder(), suite.TestGetRequest)
+}