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GitHub - plagioriginal/csvparser: A fast, easy-of-use and dependency free custom...

 2 years ago
source link: https://github.com/plagioriginal/csvparser
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csvparser

This package provides a fast and easy-of-use custom mapping from .csv data into Golang structs.

Pre-requisites

Since the library uses generics, it is necessary to have go1.18

Installation

go get github.com/plagioriginal/csvparser

Examples

Csv parsing from bytes

This will read the .csv data being sent, and will return an array of whatever you would like.

type Person struct {
	Name string
	Age int
	isInSchool bool
}
    
var input = []byte(`
name,age
frank,13
anabelle,70`)

parser := csvparser.NewCsvParserFromBytes[Person](input)
parser.AddColumnParser("name", func (value string, into *Person) error {
    into.Name = strings.Trim(value, " ")
    return nil
})
parser.AddColumnParser("age", func (value string, into *Person) error {
    value = strings.Trim(value, " ")
    age, err := strconv.Atoi(value)
    if err != nil {
        return err
    }
    into.Age = age
    if age < 18 {
	    into.IsInSchool = true	
    }
    return nil
})

// res is []Person type
res, err := parser.Parse()

Note: as long as there is a parser for the header that you want, the order of the .csv columns will not matter

What if the file doesn't have headers

When instantiating the parser, you can specify the headers of the file, in order, and the parser will handle everything for you. Just remember that the ParserHandlers need to be added.

var input = []byte(`
frank,13
anabelle,70`)

parser := csvparser.NewCsvParserFromBytes[Person](input, "name", "age")
parser.AddColumnParser("name", nameHandler)
parser.AddColumnParser("age", ageHandler)
...

Csv Parsing from multipart file / anything that applies the io.Reader

If you need to directly use something like a multipart file directly, you can do something like this:

func (h *OrderHandler) handlerFunc(w http.ResponseWriter, r *http.Request) {
    file, _, err := r.FormFile("file-key-in-request")
    if err != nil {
        ...
    }
	defer file.Close()
	parser := csvparser.NewCsvParserFromReader[WhateverStruct](file)
	...
}

Adding a hook

You can add an hook that will run everytime something is parsed from the .csv file, so that you don't have to do another loop in the results in case you want to add more logic into it.

parser := csvparser.NewCsvParserFromBytes[WhateverStruct](input)
children := make([]Person, 0)
parser.WithHook(func(parsedPerson Person) {
    if parsedPerson.IsInSchool {
        children = append(children, parsedObject)
    }
})

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