RFC6455 | I/O agnostic WebSocket Protocol | Websocket library

Looking at the source code, it appears that the message is already being fragmented, if the message exceeds the size of buffer_size.

The default size of buffer_size is 1024 bytes. You can change it in the config.

Just to illustrate a bit.

First Byte: Leftmost bit is the fin-bit rightmost 4 bits represents the opcode, in this case 1=text

10000001

Second Byte: Leftmost bit indicates if data is masked remaining seven indicate the length

10000000 here the lenght is zero
11111101 here the lenght is exactly 125

11111110 here the lenght indicator is 126 therefor the next two bytes will give you the length followed by four bytes for the mask-key

11111111 here the lenght indicator is 127 therefor the next eight bytes will give you the length followed by four bytes for the mask-key

After all this follows the masked payload.

ADDED 2021-07-19

To extract information like opcode and length, you have to apply some bit operations on the given bytes.

Below is an extraction from https://github.com/napengam/phpWebSocketServer/blob/master/server/RFC6455.php to show how the server decodes a frame.

This seems to be a problem with the virtual box filesystem. I created an issue to composer and hopefully more insight will be gained.

https://github.com/composer/package-versions-deprecated/issues/21

I found the solution, i paste there if it can help anybody... :

If your websocket service always treats every connection identically then there's no need to require a path string, or a query string, in the URI. (Well, technically you do have to have a path string, but it can be just the single character '/' every time.)

However, if your websocket service wants to be able to provide different content to different clients, then using a path string in the URI can be a convenient way for the clients to indicate what kind of content they're interested in. Perhaps your chat service offers chat rooms for several different topics, and in that case you might decide to have the client use the path string to indicate the desired topic. Something like ws://localhost:8080/sport, ws://localhost:8080/politics or ws://localhost:8080/cooking, or you could take it further and have ws://localhost:8080/sport/football, ws://localhost:8080/sport/golf and ws://localhost:8080/sport/tennis, and so on.

The "Request-URI" of the GET method [RFC2616] is used to identify the endpoint of the WebSocket connection, both to allow multiple domains to be served from one IP address ...

This is just ordinary virtual hosting. A webserver running at a single IP address can support multiple websites, based on the host part of the URI.

... and to allow multiple WebSocket endpoints to be served by a single server.

Each of the path examples I gave identifies a different, independent endpoint, all served by your one websocket server.

In this particular example the websocket endpoint is some sort of chat room, but more generally a websocket endpoint is associated with some kind of data feed, often a one-way feed (a websocket might offer a stream of current stock prices for some collection of stocks specified by a URI query string) but potentially a bidirectional feed and potentially an interactive birdirectional feed (like your chat room).

amphp/websocket-client handles pings automatically and responds to them, so receiving messages is the only concern an API user should have.

With Amp you can spawn multiple coroutines at any time using Amp\call / Amp\asyncCall, so you can e.g. close the connection after some idle time.

Setting the websocket route as below resolved the issue.

I found the answer here beyondcode/laravel-websockets issue #342 You have to create an instance of app attribute at onOpen method, here is the code:

SOLVED

I was not storing the result of readLine() in a variable, causing me to essentially discard every odd line in the response. Thanks to user207421 for pointing it out!