What are the benefits of using named tuples instead of dictionaries to define operators item types?

There are three benefits of using named tuples compared to dictionaries:

• The first is the fact that the named tuples fields can be accessed with a dot notation instead of a dictionary square-bracket-style notation. The dot notation is easier to read and write than the square bracket notation. This makes the code easier to follow.
• The second is the fact that named tuples are more efficient than dictionaries at accessing their fields. This may have a beneficial impact on performance in an application that uses such objects widely.
• The last is the fact that named tuples are immutable. Object immutability is one of the principles used in functional programming. This property allows us to follow this functional programming principle when writing a reactive application.

What is the difference between a component and a driver in Cyclotron?

A component should only contain pure functions, while a driver contains side-effects. However, there is no enforcement of this behavior in Cyclotron. It is up to the programmer to follow these principles.

How is it possible to use a function (almost) like a custom operator?

When a function takes an observable as input and returns an observable, then it makes sense to use it directly in the chain of operators instead of having to break the chain to call it. The let operator allows us to do this by wrapping the function and forwarding keyword arguments to it.

What is the type of object returned by the function provided to the flat_map operator?

The function provided to the flat_map operator returns an observable. This is different than the map operator, whose parameter function returns an item. The items emitted by the flat_map operator are then merged in the observable returned by the flat_map operator.

Why is it better to parse the JSON configuration file with the loads function rather than the load function?

The loads function parses some JSON data provided as a string parameter. This allows us to implement the JSON parsing function as a pure function. On the other hand, the load function takes a file object as input. This means that a function using the json.load function is a side-effect. Using the loads function instead of load allows us to separate pure code from the side-effects when reading the file.

Why is the fact that sox works directly on files an issue?

Reading and writing to files are side-effects. So, the sox functions that are used to convert audio contain two kinds of code: access to the files and audio manipulation. If the audio manipulation part takes buffers as input and output, it could have been implemented as a pure function. The fact that sox works directly on files makes any function using it a side-effect. This is why is has to be implemented in a driver.

Another consequence is that file access cannot occur in an asynchronous way. This means that the sox library can block the whole application if an I/O access attempt is blocked for any reason. This is why such a library should not be used in a real asynchronous application.

Find another problem in the current implementation of audio transcoding.

The current implementation of the transcoding function does not handles errors. If for any reason the encoding fails (because the provided audio cannot be decoded, for example), then the server will crash. It should instead handle the error and return an HTTP error to the client.