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WebGear API Advanced Usage:⚓

This is a continuation of the WebGear doc ➶. Thereby, It's advised to first get familiarize with this API, and its requirements.

After going through following Usage Examples, Checkout more bonus examples here ➶

Using WebGear with Variable Colorspace⚓

WebGear by default only supports "BGR" colorspace frames as input, but you can use jpeg_compression_colorspace string attribute through its options dictionary parameter to specify incoming frames colorspace.

Let's implement a bare-minimum example using WebGear, where we will be sending GRAY frames to client browser:

New in v0.2.2

This example was added in v0.2.2.

This example works in conjunction with Source ColorSpace manipulation for VideoCapture Gears ➶

Supported jpeg_compression_colorspace colorspace values are RGB, BGR, RGBX, BGRX, XBGR, XRGB, GRAY, RGBA, BGRA, ABGR, ARGB, CMYK. More information can be found here ➶

# import required libraries
import uvicorn
from vidgear.gears.asyncio import WebGear

# various performance tweaks and enable grayscale input
options = {
    "frame_size_reduction": 25,
    "jpeg_compression_colorspace": "GRAY",  # set grayscale
    "jpeg_compression_quality": 90,
    "jpeg_compression_fastdct": True,
    "jpeg_compression_fastupsample": True,
}

# initialize WebGear app and change its colorspace to grayscale
web = WebGear(
    source="foo.mp4", colorspace="COLOR_BGR2GRAY", logging=True, **options
)

# run this app on Uvicorn server at address http://0.0.0.0:8000/
uvicorn.run(web(), host="0.0.0.0", port=8000)

# close app safely
web.shutdown()

And that's all, Now you can see output at http://localhost:8000/ address on your local machine.

Using WebGear with a Custom Source(OpenCV)⚓

New in v0.2.1

This example was added in v0.2.1.

WebGear allows you to easily define your own custom Source that you want to use to transform your frames before sending them onto the browser.

JPEG Frame-Compression and all of its performance enhancing attributes are disabled with a Custom Source!

Let's implement a bare-minimum example with a Custom Source using WebGear API and OpenCV:

# import necessary libs
import uvicorn, asyncio, cv2
from vidgear.gears.asyncio import WebGear
from vidgear.gears.asyncio.helper import reducer

# initialize WebGear app without any source
web = WebGear(logging=True)

# create your own custom frame producer
async def my_frame_producer():

    # !!! define your own video source here !!!
    # Open any video stream such as live webcam 
    # video stream on first index(i.e. 0) device
    stream = cv2.VideoCapture(0)
    # loop over frames
    while True:
        # read frame from provided source
        (grabbed, frame) = stream.read()
        # break if NoneType
        if not grabbed:
            break

        # do something with your OpenCV frame here

        # reducer frames size if you want more performance otherwise comment this line
        frame = await reducer(frame, percentage=30, interpolation=cv2.INTER_AREA)  # reduce frame by 30%
        # handle JPEG encoding
        encodedImage = cv2.imencode(".jpg", frame)[1].tobytes()
        # yield frame in byte format
        yield (b"--frame\r\nContent-Type:image/jpeg\r\n\r\n" + encodedImage + b"\r\n")
        await asyncio.sleep(0)
    # close stream
    stream.release()


# add your custom frame producer to config
web.config["generator"] = my_frame_producer

# run this app on Uvicorn server at address http://localhost:8000/
uvicorn.run(web(), host="localhost", port=8000)

# close app safely
web.shutdown()

And that's all, Now you can see output at http://localhost:8000/ address.

 

Using WebGear with Custom Mounting Points⚓

With our highly extensible WebGear API, you can add your own mounting points, where additional files located, as follows:

# import libs
import uvicorn
from starlette.routing import Mount
from starlette.staticfiles import StaticFiles
from vidgear.gears.asyncio import WebGear

# various performance tweaks
options = {
    "frame_size_reduction": 40,
    "jpeg_compression_quality": 80,
    "jpeg_compression_fastdct": True,
    "jpeg_compression_fastupsample": False,
}

# initialize WebGear app
web = WebGear(
    source="foo.mp4", logging=True, **options
)  # enable source i.e. `test.mp4` and enable `logging` for debugging

# append new route i.e. mount another folder called `test` located at `/home/foo/.vidgear/test` directory
web.routes.append(
    Mount("/test", app=StaticFiles(directory="/home/foo/.vidgear/test"), name="test")
)

# run this app on Uvicorn server at address http://localhost:8000/
uvicorn.run(web(), host="localhost", port=8000)

# close app safely
web.shutdown()

Then you can use this folder in your HTML page, to host data-files. For example, if we have jQuery script jquery-3.3.1.slim.min.js in this folder and want to integrate it, then, we can do something like this:

<script src="{{ url_for('test', path='jquery-3.3.1.slim.min.js') }}"></script>

 

Using WebGear with Custom Webpage Routes⚓

With Webgear's flexible API, you can even add your additional HTML Static webpages without any extra efforts.

Suppose we want to add a simple hello world webpage to our WebGear server. So let's create a bare-minimum hello.html file with HTML code as follows:

<html>
   <header>
      <title>This is Hello world page</title>
   </header>
   <body>
      <h1>Hello World</h1>
      <p>how ya doing?</p>
   </body>
</html>

Then in our application code, we can integrate this webpage route, as follows:

# import libs
import uvicorn, asyncio
from starlette.templating import Jinja2Templates
from starlette.routing import Route
from vidgear.gears.asyncio import WebGear

# Build out Jinja2 template render at `/home/foo/.vidgear/custom_template` path in which our `hello.html` file is located
template = Jinja2Templates(directory="/home/foo/.vidgear/custom_template")

# render and return our webpage template
async def hello_world(request):
    page = "hello.html"
    context = {"request": request}
    return template.TemplateResponse(page, context)


# add various performance tweaks as usual
options = {
    "frame_size_reduction": 40,
    "jpeg_compression_quality": 80,
    "jpeg_compression_fastdct": True,
    "jpeg_compression_fastupsample": False,
}

# initialize WebGear app with a valid source
web = WebGear(
    source="/home/foo/foo1.mp4", logging=True, **options
)  # enable source i.e. `test.mp4` and enable `logging` for debugging

# append new route to point our rendered webpage
web.routes.append(Route("/hello", endpoint=hello_world))

# run this app on Uvicorn server at address http://localhost:8000/
uvicorn.run(web(), host="localhost", port=8000)

# close app safely
web.shutdown()
And that's all, Now you can see output at http://localhost:8000/hello address.

 

Using WebGear with MiddleWares⚓

WebGear natively supports ASGI middleware classes with Starlette for implementing behavior that is applied across your entire ASGI application easily.

New in v0.2.2

This example was added in v0.2.2.

All supported middlewares can be found here ➶

For this example, let's use CORSMiddleware for implementing appropriate CORS headers to outgoing responses in our application in order to allow cross-origin requests from browsers, as follows:

The default parameters used by the CORSMiddleware implementation are restrictive by default, so you'll need to explicitly enable particular origins, methods, or headers, in order for browsers to be permitted to use them in a Cross-Domain context.

Starlette provides several arguments for enabling origins, methods, or headers for CORSMiddleware API. More information can be found here ➶

# import libs
import uvicorn, asyncio
from starlette.middleware import Middleware
from starlette.middleware.cors import CORSMiddleware
from vidgear.gears.asyncio import WebGear

# add various performance tweaks as usual
options = {
    "frame_size_reduction": 40,
    "jpeg_compression_quality": 80,
    "jpeg_compression_fastdct": True,
    "jpeg_compression_fastupsample": False,
}

# initialize WebGear app with a valid source
web = WebGear(
    source="/home/foo/foo1.mp4", logging=True, **options
)  # enable source i.e. `test.mp4` and enable `logging` for debugging

# define and assign suitable cors middlewares
web.middleware = [
    Middleware(
        CORSMiddleware,
        allow_origins=["*"],
        allow_credentials=True,
        allow_methods=["*"],
        allow_headers=["*"],
    )
]

# run this app on Uvicorn server at address http://localhost:8000/
uvicorn.run(web(), host="localhost", port=8000)

# close app safely
web.shutdown()
And that's all, Now you can see output at http://localhost:8000 address.

 

Rules for Altering WebGear Files and Folders⚓

WebGear gives us complete freedom of altering data files generated in Auto-Generation Process, But you've to keep the following rules in mind:

Rules for Altering Data Files⚓

  • You allowed to alter/change code in all existing default downloaded files at your convenience without any restrictions.
  • You allowed to delete/rename all existing data files, except remember NOT to delete/rename three critical data-files (i.e index.html, 404.html & 500.html) present in templates folder inside the webgear directory at the default location, otherwise, it will trigger Auto-generation process, and it will overwrite the existing files with Server ones.
  • You're allowed to add your own additional .html, .css, .js, etc. files in the respective folders at the default location and custom mounted Data folders.

Rules for Altering Data Folders⚓

  • You're allowed to add/mount any number of additional folder as shown in this example above.
  • You're allowed to delete/rename existing folders at the default location except remember NOT to delete/rename templates folder in the webgear directory where critical data-files (i.e index.html, 404.html & 500.html) are located, otherwise, it will trigger Auto-generation process.

 

Bonus Examples⚓

Checkout more advanced WebGear examples with unusual configuration here ➶

 


Last update: June 27, 2022