Categorygithub.com/pschlump/mapstructure
modulepackage
1.0.9
Repository: https://github.com/pschlump/mapstructure.git
Documentation: pkg.go.dev

# README

mapstructure

license

mapstructure is a Go library for decoding generic map values to structures and vice versa, while providing helpful error handling.

This library is most useful when decoding values from some data stream (JSON, Gob, etc.) where you don't quite know the structure of the underlying data until you read a part of it. You can therefore read a map[string]interface{} and use this library to decode it into the proper underlying native Go structure.

Installation

Standard go get:

$ go get github.com/pschlump/mapstructure

Usage & Example

For usage and examples see the Godoc.

The Decode function has examples associated with it there.

But Why?!

Go offers fantastic standard libraries for decoding formats such as JSON. The standard method is to have a struct pre-created, and populate that struct from the bytes of the encoded format. This is great, but the problem is if you have configuration or an encoding that changes slightly depending on specific fields. For example, consider this JSON:

{
  "type": "person",
  "name": "Mitchell"
}

Perhaps we can't populate a specific structure without first reading the "type" field from the JSON. We could always do two passes over the decoding of the JSON (reading the "type" first, and the rest later). However, it is much simpler to just decode this into a map[string]interface{} structure, read the "type" key, then use something like this library to decode it into the proper structure.

# Functions

ComposeDecodeHookFunc creates a single DecodeHookFunc that automatically composes multiple DecodeHookFuncs.
Decode takes a map and uses reflection to convert it into the given Go native structure.
DecodeHookExec executes the given decode hook.
NewDecoder returns a new decoder for the given configuration.
StringToSliceHookFunc returns a DecodeHookFunc that converts string to []string by splitting on the given sep.
StringToTimeDurationHookFunc returns a DecodeHookFunc that converts strings to time.Duration.
WeakDecode is the same as Decode but is shorthand to enable WeaklyTypedInput.
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# Structs

A Decoder takes a raw interface value and turns it into structured data, keeping track of rich error information along the way in case anything goes wrong.
DecoderConfig is the configuration that is used to create a new decoder and allows customization of various aspects of decoding.
Error implements the error interface and can represents multiple errors that occur in the course of a single decode.
Metadata contains information about decoding a structure that is tedious or difficult to get otherwise.

# Interfaces

DecodeHookFunc is the callback function that can be used for data transformations.

# Type aliases

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