implement REST interface

yashhere · Feb 13, 2019 · 287124f · 287124f
1 parent 25a7792
commit 287124f
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Showing 3 changed files with 76 additions and 6 deletions.
diff --git a/api/library.proto b/api/library.proto
@@ -1,14 +1,44 @@
 syntax = "proto3";
 package library;
 import "google/protobuf/timestamp.proto";
+import "google/api/annotations.proto";
 
 service LibraryService {
-  rpc ListAllBooks(Empty) returns (Books);
-  rpc AddBook(Book) returns (Response);
-  rpc DeleteBook(QueryFormat) returns (Response);
-  rpc SearchBook(QueryFormat) returns (Response);
-  rpc IssueBook(QueryFormat) returns (Response);
-  rpc ReturnBook(QueryFormat) returns (Response);
+  rpc ListAllBooks(Empty) returns (Books) {
+    option (google.api.http) = {
+      get : "/listBooks"
+    };
+  };
+  rpc AddBook(Book) returns (Response) {
+    option (google.api.http) = {
+      post : "/addBook"
+      body : "*"
+    };
+  };
+  rpc DeleteBook(QueryFormat) returns (Response) {
+    option (google.api.http) = {
+      post : "/deleteBook"
+      body : "*"
+    };
+  };
+  rpc SearchBook(QueryFormat) returns (Response) {
+    option (google.api.http) = {
+      post : "/searchBook"
+      body : "*"
+    };
+  };
+  rpc IssueBook(QueryFormat) returns (Response) {
+    option (google.api.http) = {
+      post : "/issueBook"
+      body : "*"
+    };
+  };
+  rpc ReturnBook(QueryFormat) returns (Response) {
+    option (google.api.http) = {
+      post : "/returnBook"
+      body : "*"
+    };
+  };
 }
 
 // the library

diff --git a/cmd/main.go b/cmd/main.go
@@ -12,6 +12,7 @@ const (
 )
 
 func main() {
+	clientAddr := fmt.Sprintf("localhost%s", port)
 	lis, err := net.Listen("tcp", port)
 	if err != nil {
 		log.Fatalf("failed to listen: %v", err)
@@ -23,5 +24,6 @@ func main() {
 	}()
 
 	library.InitializeLibrary()
+	go library.StartHTTPServer(clientAddr)
 	library.StartLibraryServer(lis)
 }
diff --git a/pkg/librarylib/server.go b/pkg/librarylib/server.go
@@ -2,12 +2,16 @@ package server
 
 import (
 	"context"
+	"encoding/json"
 	"fmt"
 	"log"
 	"net"
+	"net/http"
 	"os"
 	"time"
 
+	"github.com/grpc-ecosystem/grpc-gateway/runtime"
+
 	library "personal-learning/go-library/api"
 
 	ptypes "github.com/golang/protobuf/ptypes"
@@ -21,6 +25,10 @@ var (
 
 type server struct{}
 
+type errorBody struct {
+	Err string `json:"error,omitempty"`
+}
+
 /*
 InitializeLibrary is used to Initialize the libraryData variable.
 We are using a global variable to store our library data. This way
@@ -279,6 +287,21 @@ func (s *server) ReturnBook(ctx context.Context, query *library.QueryFormat) (*l
 	return res, nil
 }
 
+// StartHTTPServer - Start the HTTP Server
+func StartHTTPServer(clientAddr string) {
+	log.Printf("Starting HTTP Server...")
+	runtime.HTTPError = CustomHTTPError
+
+	addr := ":8181"
+	opts := []grpc.DialOption{grpc.WithInsecure()}
+	mux := runtime.NewServeMux()
+	if err := library.RegisterLibraryServiceHandlerFromEndpoint(context.Background(), mux, clientAddr, opts); err != nil {
+		log.Fatalf("failed to start HTTP server: %v", err)
+	}
+	log.Printf("HTTP Listening on %s\n", addr)
+	log.Fatal(http.ListenAndServe(addr, mux))
+}
+
 // StartLibraryServer - Start the GRPC Server
 func StartLibraryServer(lis net.Listener) {
 	log.Printf("Starting GRPC server...")
@@ -292,3 +315,18 @@ func StartLibraryServer(lis net.Listener) {
 		os.Exit(1)
 	}
 }
+
+// CustomHTTPError - Custom HTTP error on errors in StartHTTPServer
+func CustomHTTPError(ctx context.Context, _ *runtime.ServeMux, marshaler runtime.Marshaler, w http.ResponseWriter, _ *http.Request, err error) {
+	const fallback = `{"error": "failed to marshal error message"}`
+
+	w.Header().Set("Content-type", marshaler.ContentType())
+	w.WriteHeader(runtime.HTTPStatusFromCode(grpc.Code(err)))
+	jErr := json.NewEncoder(w).Encode(errorBody{
+		Err: grpc.ErrorDesc(err),
+	})
+
+	if jErr != nil {
+		w.Write([]byte(fallback))
+	}
+}