How to Deserialize Serialized JSON into a Rust Object

A beginner's guide for Rust programmers on how to deserialize a string of serialized JSON into a Rust object using serde_json.
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How to Deserialize Serialized JSON into a Rust Object

As a new Rust programmer, you may find yourself in situations where you need to take serialized JSON data, which is often in a string format, and convert it into a Rust object. This task can be a bit tricky if you're unfamiliar with the intricacies of JSON handling in Rust. In this post, we’ll break down how to deserialize serialized JSON into a Rust object step-by-step, using the serde_json crate.

Understanding the Problem

[[See Video to Reveal this Text or Code Snippet]]

This string appears to have been encoded in JSON format twice, which is why deserializing it directly will yield errors. The aim is to take this string, decode it, and create a proper Rust object out of it without prior knowledge of its structure.

Solution Overview

[[See Video to Reveal this Text or Code Snippet]]

Once that's set up, you can proceed with the following Rust code.

Step-by-Step Code Explanation

Read the JSON text: Since you're working with a string directly in this case, let's define the string instead of reading it from a file.

First Deserialization: Convert the outer JSON string to a Rust String type. You must perform this step first because your data is already in a JSON format as a string.

Second Deserialization: Parse the resultant string to create a serde_json::Value, which is a dynamic way to handle JSON data in Rust.

Here’s the full example of how you can implement this:

[[See Video to Reveal this Text or Code Snippet]]

Explanation of Code

let j = r-"...-": This defines a raw string literal containing the double-encoded JSON string.

serde_json::from_str(j): This line takes the string j and tries to convert it into a String. If the conversion fails, it panics with the message “not a string.”

dbg!(&v): This is a debugging macro that prints the intermediate String result.

serde_json::from_str(&v): This final line takes the first deserialized result and turns it into a serde_json::Value object, allowing for further manipulation or access to the data.

Conclusion

By following the above steps, you can easily convert serialized JSON strings into usable Rust objects using the serde_json library. This technique is particularly useful when working with dynamic JSON data where the structure is not predefined. As you grow more comfortable with Rust and JSON handling, you'll find these skills invaluable in building robust applications.

Happy coding!