add ctx metadata

.gitignore

@@ -1,3 +1,5 @@
 grpcox
 log
-*.out
+*.out
+vendor/
+.idea

core/resource.go

@@ -184,7 +184,7 @@ func (r *Resource) Describe(symbol string) (string, string, error) {
 }
 
 // Invoke - invoking gRPC function
-func (r *Resource) Invoke(ctx context.Context, symbol string, in io.Reader) (string, time.Duration, error) {
+func (r *Resource) Invoke(ctx context.Context, metadata []string, symbol string, in io.Reader) (string, time.Duration, error) {
 	err := r.openDescriptor()
 	if err != nil {
 		return "", 0, err
@@ -210,8 +210,13 @@ func (r *Resource) Invoke(ctx context.Context, symbol string, in io.Reader) (str
 	}
 	h := grpcurl.NewDefaultEventHandler(os.Stdout, r.descSource, formatter, false)
 
+	var headers = r.headers
+	if len(metadata) != 0 {
+		headers = metadata
+	}
+
 	start := time.Now()
-	err = grpcurl.InvokeRPC(ctx, r.descSource, r.clientConn, symbol, r.headers, h, rf.Next)
+	err = grpcurl.InvokeRPC(ctx, r.descSource, r.clientConn, symbol, headers, h, rf.Next)
 	end := time.Now().Sub(start) / time.Millisecond
 	if err != nil {
 		return "", end, err

handler/handler.go

@@ -221,8 +221,26 @@ func (h *Handler) invokeFunction(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	// context metadata
+	metadataHeader := r.Header.Get("Metadata")
+	metadataArr := strings.Split(metadataHeader, ",")
+
+	// construct array of string with "key: value" form to satisfy grpcurl MetadataFromHeaders
+	var metadata []string
+	var metadataStr string
+	for i, m := range metadataArr {
+		i += 1
+		if isEven := i % 2 == 0; isEven {
+			metadataStr = metadataStr+m
+			metadata = append(metadata, metadataStr)
+			metadataStr = ""
+			continue
+		}
+		metadataStr = fmt.Sprintf("%s:", m)
+	}
+
 	// get param
-	result, timer, err := res.Invoke(context.Background(), funcName, r.Body)
+	result, timer, err := res.Invoke(context.Background(), metadata, funcName, r.Body)
 	if err != nil {
 		writeError(w, err)
 		return

index/index.html

@@ -47,6 +47,50 @@
             <div class="proto-collection"></div>
         </div>
 
+        <!-- Context metadata -->
+        <div class="input-group">
+          <div class="custom-control custom-checkbox">
+            <input type="checkbox" class="custom-control-input" id="ctx-metadata-switch">
+            <label class="custom-control-label" for="ctx-metadata-switch">Use request metadata</label>
+          </div>
+        </div>
+
+        <div class="input-group" id="ctx-metadata-input" style="display: none">
+          <br>
+          <div id="ctx-metadata-table" class="table-editable">
+            <table class="table table-bordered">
+              <thead>
+                <tr>
+                  <th class="text-start" style="width: 10%"></th>
+                  <th class="text-start" style="width: 20%">Key</th>
+                  <th class="text-start" style="width: 70%">Value</th>
+                </tr>
+              </thead>
+              <tbody>
+                <tr>
+                  <td>
+                        <span class="table-remove">
+                          <button type="button" class="btn btn-danger btn-rounded btn-sm my-0">
+                            <i class="fa fa-times"></i>
+                          </button>
+                        </span>
+                  </td>
+                  <td class="ctx-metadata-input-field pt-3-half" contenteditable="true"></td>
+                  <td class="ctx-metadata-input-field pt-3-half" contenteditable="true"></td>
+                </tr>
+              </tbody>
+            </table>
+            <div class="input-group-append">
+                  <span class="table-add">
+                    <button type="button" class="btn btn-success btn-rounded btn-sm my-0">
+                      <i class="fa fa-plus"></i>
+                    </button>
+                  </span>
+            </div>
+          </div>
+        </div>
+        <!-- Context metadata -->
+
         <div class="other-elem" id="choose-service" style="display: none">
           <div class="input-group">
             <div class="input-group-prepend">
@@ -138,6 +182,7 @@
   <script src="https://cdnjs.cloudflare.com/ajax/libs/ace/1.4.1/ace.js"></script>
   <script type="text/javascript" src="js/style.js"></script>
   <script type="text/javascript" src="js/proto.js"></script>
+  <script type="text/javascript" src="js/ctx.metadata.js"></script>
 </body>
 
 </html>

index/js/ctx.metadata.js

@@ -0,0 +1,64 @@
+// table input for context metadata
+const ctxMetadataTable = $('#ctx-metadata-table');
+
+// new row for each context being added
+const newTr = `
+    <tr>
+        <td>
+          <span class="table-remove">
+            <button type="button" class="btn btn-danger btn-rounded btn-sm my-0">
+              <i class="fa fa-times"></i>
+            </button>
+          </span>
+        </td>
+        <td class="ctx-metadata-input-field pt-3-half" contenteditable="true"></td>
+        <td class="ctx-metadata-input-field pt-3-half" contenteditable="true"></td>
+     </tr>`;
+
+// helper variable to contains all of the context metadata input
+let ctxArr = [];
+
+// helper variable to contain the usage of metadata
+let ctxUse = false;
+
+// ctx metadata event listener
+(function () {
+    // add event listener on ctx metadata checkbox
+    const ctxMetadataSwitch = document.getElementById("ctx-metadata-switch");
+    ctxMetadataSwitch.addEventListener("change", function(event) {
+        const { checked } = event.target;
+        ctxUse = checked;
+        toggleDisplayCtxMetadataTable(checked);
+    });
+
+    // remove for each row in ctx metadata table
+    ctxMetadataTable.on('click', '.table-remove', function () {
+        $(this).parents('tr').detach();
+    });
+
+    // add new row
+    ctxMetadataTable.on('click', '.table-add', () => {
+        $('tbody').append(newTr);
+    });
+
+    // only allow any paste action with plain text
+    ctxMetadataTable.on('paste', '.ctx-metadata-input-field', function (e) {
+        // cancel paste
+        e.preventDefault();
+        // get text representation of clipboard
+        const text = (e.originalEvent || e).clipboardData.getData('text/plain');
+        // insert text manually
+        document.execCommand("insertHTML", false, text);
+    });
+
+}());
+
+// toggle ctx metadata display
+// will show the key-value pairs table input
+function toggleDisplayCtxMetadataTable(show) {
+    const style = show ? "display: block" : "display: none";
+
+    const protoInput = document.getElementById("ctx-metadata-input");
+    protoInput.removeAttribute("style");
+    protoInput.style.cssText = style;
+}

index/js/style.js

@@ -135,6 +135,13 @@ $('#select-function').change(function(){
 });
 
 $('#invoke-func').click(function(){
+
+    // use metadata if there is any
+    ctxArr = [];
+    $(".ctx-metadata-input-field").each(function(index, val){
+        ctxArr.push($(val).text())
+    });
+
     var func = $('#select-function').val();
     if (func == "") {
         return false;
@@ -160,6 +167,9 @@ $('#invoke-func').click(function(){
         beforeSend: function(xhr){
             $('#response').hide();
             xhr.setRequestHeader('use_tls', use_tls);
+            if(ctxUse) {
+                xhr.setRequestHeader('Metadata', ctxArr);
+            }
             $(this).html("Loading...");
             show_loading();
         },