Hi Caitlin,

Thanks for the insight, I cannot find a public interface for 
debug::SetConsoleDelegate() so I guess that's not an option.  I guess I 
could look at the inspector API and see what I can find there.   Right now 
I think I am favoring the simplicity of the other suggestion to just roll 
my own object and replace the default one. 

Thanks for the pointer though, and of course the response, if I do find a 
way to do this I will post back for others. 

Thank you,

Gerry


On Tuesday, February 5, 2019 at 3:12:28 PM UTC, Caitlin Potter wrote:
>
>
>
> > On Feb 5, 2019, at 10:02 AM, Gerry Sweeney <gez...@gmail.com 
> <javascript:>> wrote: 
> > 
> > Hello Caitlin, 
> > 
> > First of all, thank you for your response, and yes you are right I 
> should have been far clearer in my question, please let me clarify. 
> > 
> > I have a process, is an x64 C++ application that normally runs as a 
>  Windows service or a Linux Deamon, its job is to provide a way for our 
> user to write application logic in JavaScript, which we then invoke using a 
> REST type API.  Under normal circumstances, this project runs as a service, 
> but when working on the code, it's essentially running as a Windows console 
> application, anything emitted on stdout appears in the console window of 
> the running process. The process is conceptually similar to a Node.js 
> server process. 
> > 
> > This process is written in C++ and embeds V8, and in the current model, 
> we create an Isolate and Context per API request made, and when we process 
> a request, we are loading some JavaScript from a cache and executing it.   
> As part of the embedding, we have created a number of native objects in C++ 
> that are exposed in the JavaScript domain, classes that provide access to 
> the underlying database, memory cache and other relates to web services. 
> > 
> > When we write JavaScript we have to debug it, and in the absence of 
> using CDT for remote debugging (which we are in the process of 
> implementing), we could at least do with using console.log().  We have 
> implemented a websocket interface that on a call by call basis allows our 
> C++ code to send arbitrary content back to the developer (of the 
> JavaScript) workstation. 
> > 
> > So I need a way of implementing console.log() where I can redirect its 
> output to my own websocket.  My intention was to create an object called 
> "console" and create a function on that object called "log()" and create an 
> instance of that object in the global namespace, thus simulating the 
> console.log() web developers are used in browsers. 
> > 
> > However, what I found is, without me creating these objects, they appear 
> to already exist in the default implementation of v8. In other words, if I 
> write  console.log("Hello, World") the script runs without error, which 
> tells me that the console object exists, and the log() function exists. 
> > 
> > So rather than re-invent the wheel and implement my own version of 
> console.log() I thought it might just be simpler to find a way to capture 
> the output of what already exists.  Thing is, I have no idea where to 
> start. 
> > 
> > Also, which console.log() implementation are you using? The one from 
> d8-console.cc? One from Node.js or Chromium? A custom one? 
> > I am assuming that the embedded V8 library includes by default the 
> console object 
>
> Ah I see you're right, this is now included in the initial context. It 
> looks like you need to use `debug::SetConsoleDelegate(isolate, 
> ConsoleDelegate*)` in order to provide the behaviour you want --- however, 
> I'm not sure how this is exposed to the public API. Inspector folks could 
> help more with that. 
>
> It looks like by default, the Isolate's console_delegate_ is null, and the 
> builtin console.log returns early if that's the case. 
>
> > We are using 6.9.167 of the v8 engine in this project. 
> > 
> > I hope that makes more sense now - sorry for the poor quality initial 
> question. 
> > Gerry 
> > 
> > 
> > -- 
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