deflectjs-engine/README.md

Make it easier to hook APIs and functions into javascript using DeflectJS API Hooking.

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# DeflectJS API - Hooking
Make it easier to hook APIs and functions into javascript using DeflectJS API Hooking. If you want install it in node, please check our npm package deflectjs-engine.

### Get started into DeflectJS Hooking Engine
  
Our example will show how to change the behavior of the console.log function using a replacement hook. 
 
The console.log by default display a text parameter specified in log(str), thus let's change the real output to "Hooked: " + str. When an user call console.log(str) the string displayed should be "Hooked: " + str. After attach our hook, console.log("Test!") will give "Hooked: Test!" instead of "Test!".

Original output when calling console.log 

<p align="left">
    <img src="https://i.imgur.com/Su9MVXi.png" alt="Hooked: Test!" style="display:block;">
</p> 

### Hooking the function console.log using DeflectJS Hooking Engine

```javascript
var hookStruct; //Struct that contains our hook data.
var hookQueue = []; //Queue where our hook will be added.

//Function that will replace the current console.log
function hookedLog(text){
    return hookStruct.OriginalFunction("Hooked: " + text); 
}

//Creating the stub that will intercept calls for console.log
hookStruct = deflect_create_native_hook(console.log, hookedLog, DEFLECT_NATIVE_OVERWRITTEN_HOOK, console);

//Adding the hooks in the queue to be attached.
if (deflect_enqueue_hook(hookStruct, hookQueue) != DEFLECT_STATE_ENQUEUED){
    alert('Error!');
}

//Attaching all hooks in queue.
if (deflect_attach_hook(hookQueue) != DEFLECT_STATE_HOOKED){
    alert('Error!');
}
```

After hooking the console.log api, let's see what happens when you call it.

```javascript
//Now, let's see what happens when call console.log
console.log("Test!");
```

And our result will be:

<p align="left">
    <img src="https://i.imgur.com/LUtyZEM.png" alt="Hooked: Test!" style="display:block;">
</p>

### Unhooking the function console.log using DeflectJS Hooking Engine
```javascript
if (deflect_detach_hook(hookQueue) == DEFLECT_STATE_UNHOOKED){
    alert('Successful unhooked!');
}
```

### Compatibility of modern browsers

<center>

|     Browser     |  Verified version | Supported features |
|:---------------:|:-----------------:|:------------------:|
|  Google Chrome  |   v79.0.3945.88   |    All features    |
| Mozilla Firefox |       v71.0       |    All features    |
|      Opera      |   v65.0.3467.78   |    All features    |
|  Microsoft Edge | v20.10240.16384.0 |    All features    |

</center>

### Malicious use of DeflectJS Hooking Engine
When a function is hooked its behavior changes and leads to different results than the application intended. Malicious use of hooks to exploit systems is discouraged and isn't our responsibility. 

### Wiki of DeflectJS Engine Hooking
Visit our [wiki page](https://github.com/MurylloEx/DeflectJS-API-Hooking/wiki) and read our api sample.