attempt at primitive DI, mock own rest client

app/webmention/handler.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 
 	"github.com/wgroeneveld/go-jamming/common"
+    "github.com/wgroeneveld/go-jamming/rest"
 )
 
 func HandleGet(conf *common.Config) http.HandlerFunc {
@@ -21,26 +22,31 @@ func HandlePut(conf *common.Config) http.HandlerFunc {
 }
 
 func HandlePost(conf *common.Config) http.HandlerFunc {
+    httpClient := &rest.HttpClient{}
+
     return func(w http.ResponseWriter, r *http.Request) {
     	r.ParseForm()
     	if !validate(r, r.Header, conf) {
-    		common.BadRequest(w)
+    		rest.BadRequest(w)
     		return
     	}
     	
     	target := r.FormValue("target")
-    	if !isValidTargetUrl(target) {
-    		common.BadRequest(w)
+    	if !isValidTargetUrl(target, httpClient) {
+    		rest.BadRequest(w)
     		return
     	}
 
-    	wm := &webmention{
+    	wm := webmention{
             source: r.FormValue("source"),
             target: target,
-        } 
+        }
+        recv := &receiver{
+            restClient: httpClient,
+        }
 
-        go wm.receive()
-        common.Accept(w)
+        go recv.receive(wm)
+        rest.Accept(w)
     }
 }
 

app/webmention/receive.go

@@ -4,7 +4,7 @@ package webmention
 import (
 	"fmt"
 
-	"github.com/wgroeneveld/go-jamming/common"
+	"github.com/wgroeneveld/go-jamming/rest"
 
 	"github.com/rs/zerolog/log"
 )
@@ -18,23 +18,29 @@ func (wm *webmention) String() string {
     return fmt.Sprintf("source: %s, target: %s", wm.source, wm.target)
 }
 
-func (wm *webmention) receive() {
+// used as a "class" to iject dependencies, just to be able to test. Do NOT like htis. 
+// Is there a better way? e.g. in validate, I just pass rest.Client as an arg. Not great either. 
+type receiver struct {
+	restClient rest.Client
+}
+
+func (recv *receiver) receive(wm webmention) {
 	log.Info().Str("webmention", wm.String()).Msg("OK: looks valid")
-	body, geterr := common.Get(wm.source)
+	body, geterr := recv.restClient.GetBody(wm.source)
 
 	if geterr != nil {
         log.Warn().Str("source", wm.source).Msg("  ABORT: invalid url")
-		wm.deletePossibleOlderWebmention()
+		recv.deletePossibleOlderWebmention(wm)
 		return
 	}
 
-	wm.processSourceBody(body)	
+	recv.processSourceBody(body, wm)
 }
 
-func (wm *webmention) deletePossibleOlderWebmention() {
+func (recv *receiver) deletePossibleOlderWebmention(wm webmention) {
 
 }
 
-func (wm *webmention) processSourceBody(body string) {
+func (recv *receiver) processSourceBody(body string, wm webmention) {
 	
 }

app/webmention/validate.go

@@ -3,9 +3,9 @@ package webmention
 
 import (
 	"strings"
-	"net/http"
 
 	"github.com/wgroeneveld/go-jamming/common"
+	"github.com/wgroeneveld/go-jamming/rest"
 
 	"github.com/rs/zerolog/log"
 )
@@ -24,16 +24,8 @@ func isValidDomain(url string, conf *common.Config) bool {
 	return false
 }
 
-// great, these are needed to do the structural typing for the tests...
-type httpReq interface {
-	FormValue(key string) string
-}
-type httpHeader interface {
-	Get(key string) string
-}
-
-func isValidTargetUrl(url string) bool {
-	_, err := http.Get(url)
+func isValidTargetUrl(url string, httpClient rest.Client) bool {
+	_, err := httpClient.Get(url)
 	if err != nil {
 		log.Warn().Str("target", url).Msg("Invalid target URL")
 		return false
@@ -41,7 +33,7 @@ func isValidTargetUrl(url string) bool {
 	return true
 }
 
-func validate(r httpReq, h httpHeader, conf *common.Config) bool {
+func validate(r rest.HttpReq, h rest.HttpHeader, conf *common.Config) bool {
 	return h.Get("Content-Type") == "application/x-www-form-urlencoded" &&
 		isValidUrl(r.FormValue("source")) &&
 		isValidUrl(r.FormValue("target")) &&

app/webmention/validate_test.go

@@ -3,6 +3,8 @@ package webmention
 
 import (
 	"testing"
+	"errors"
+	"net/http"
 
 	"github.com/wgroeneveld/go-jamming/common"
 )
@@ -109,7 +111,34 @@ func TestValidate(t *testing.T) {
 				t.Fatalf("got %v, want %v", actual, tc.expected)
 			}
 		})
-	}
-
-	
+	}	
+}
+
+type restClientMock struct {
+}
+
+func (client *restClientMock) Get(url string) (*http.Response, error) {
+	if url == "failing" {
+		return nil, errors.New("whoops")
+	}
+	return nil, nil
+}
+func (client *restClientMock) GetBody(url string) (string, error) {
+	return "", nil
+}
+
+func TestIsValidTargetUrlFalseIfGetFails(t *testing.T) {
+	client := &restClientMock{}
+	result := isValidTargetUrl("failing", client)
+	if result != false {
+		t.Fatalf("expected to fail")
+	}
+}
+
+func TestIsValidTargetUrlTrueIfGetSucceeds(t *testing.T) {
+	client := &restClientMock{}
+	result := isValidTargetUrl("valid stuff!", client)
+	if result != true {
+		t.Fatalf("expected to succeed")
+	}
 }

rest/client.go

@@ -1,23 +1,22 @@
 
-package common
+package rest
 
 import (
 	"fmt"
 	"net/http"
-	"io/ioutil"
+	"io/ioutil"	
 )
 
-func BadRequest(w http.ResponseWriter) {
-	http.Error(w, "400 bad request", http.StatusBadRequest)
+type Client interface {
+	Get(url string) (*http.Response, error)
+	GetBody(url string) (string, error)
 }
 
-func Accept(w http.ResponseWriter) {
-	w.WriteHeader(202)
-	w.Write([]byte("Thanks, bro. Will send these webmentions soon, pinky swear!"))
+type HttpClient struct {
 }
 
 // something like this? https://freshman.tech/snippets/go/http-response-to-string/
-func Get(url string) (string, error) {
+func (client *HttpClient) GetBody(url string) (string, error) {
 	resp, geterr := http.Get(url)
 	if geterr != nil {
 		return "", geterr
@@ -35,3 +34,8 @@ func Get(url string) (string, error) {
 
 	return string(body), nil
 }
+
+
+func (client *HttpClient) Get(url string) (*http.Response, error) {
+	return http.Get(url)
+}

rest/utils.go

@@ -0,0 +1,15 @@
+
+package rest
+
+import (
+	"net/http"
+)
+
+func BadRequest(w http.ResponseWriter) {
+	http.Error(w, "400 bad request", http.StatusBadRequest)
+}
+
+func Accept(w http.ResponseWriter) {
+	w.WriteHeader(202)
+	w.Write([]byte("Thanks, bro. Will send these webmentions soon, pinky swear!"))
+}

rest/wrappers.go

@@ -0,0 +1,10 @@
+
+package rest
+
+// great, these are needed to do the structural typing for the tests...
+type HttpReq interface {
+	FormValue(key string) string
+}
+type HttpHeader interface {
+	Get(key string) string
+}