implement some chromium commands

chromium.js

@@ -17,8 +17,42 @@ class HeadlessChromium
 		var command = {id: 0, method: method, params: params}
 		this.websocket.send(JSON.stringify(command))
 		this.websocket.onmessage = (response) => {		
-			callback(response.data)
+			callback(JSON.parse(response.data))
 		}
 	}
+	
+	openNewPage(url, callback)
+	{
+		this.runCommand("Target.createTarget", {url: url}, (response) => {
+			callback(response.result.targetId)
+		})
+	}
+	
+	closePage(page, callback)
+	{
+		this.runCommand("Target.closeTarget", {targetId: page}, (response) => {
+			callback()
+		})
+	}
+	
+	focusPage(page, callback)
+	{
+		this.runCommand("Target.activateTarget", {targetId: page}, (response) => {
+			this.runCommand("Target.attachToTarget", {targetId:page}, (response) => {
+				callback()
+			})
+		})
+	}
+	
+	// todo: does not work yet
+	printToPdf(callback)
+	{
+		this.runCommand("Page.enable", {}, (ignored) => {
+			console.log("Page.enable: " + JSON.stringify(ignored))
+			this.runCommand("Page.printToPDF", {}, (response) => {
+				console.log("Page.printToPDF:" +  JSON.stringify(response))
+			})
+		})
+	}
 }
 

index.html

@@ -11,20 +11,33 @@
     		var websocketUrl = searchParams.get("websocket")
     		var browser = new HeadlessChromium(websocketUrl)
     		
-    		function mainloop()
+    		function html2pdf(url, callback)
     		{
-    			if (browser.isConnected())
-    			{
-    				browser.runCommand("Browser.getVersion", {}, (version) => {
-    					console.log(version)
-    				})
-    			}
-    			else
+    			if (!browser.isConnected())
     			{
-    				console.log("Not connected!")
+    				console.log("Browser is not connected!")
+    				callback(null)
+    				return
     			}
-
-    			setTimeout(mainloop, 2 /* seconds */ * 1000) 
+    			
+    			browser.openNewPage(url, (page) => {
+    				browser.focusPage(page, () => {
+    					browser.printToPdf(() => {
+					 		browser.closePage(page, () => {
+					 			console.log("close")
+					 		})
+					 	})
+       				})
+    			})
+    		}
+    		
+    		function mainloop()
+    		{
+				html2pdf("http://www.example.com", (pdf) => {
+					console.log(pdf)
+					
+					setTimeout(mainloop, 5 /* seconds */ * 1000) 
+				})
     		}
     		mainloop()
     	</script>