# YAML marshaling and unmarshaling support for Go [![Build Status](https://travis-ci.org/ghodss/yaml.svg)](https://travis-ci.org/ghodss/yaml) ## Introduction A wrapper around [go-yaml](https://github.com/go-yaml/yaml) designed to enable a better way of handling YAML when marshaling to and from structs. In short, this library first converts YAML to JSON using go-yaml and then uses `json.Marshal` and `json.Unmarshal` to convert to or from the struct. This means that it effectively reuses the JSON struct tags as well as the custom JSON methods `MarshalJSON` and `UnmarshalJSON` unlike go-yaml. For a detailed overview of the rationale behind this method, [see this blog post](http://ghodss.com/2014/the-right-way-to-handle-yaml-in-golang/). ## Compatibility This package uses [go-yaml](https://github.com/go-yaml/yaml) and therefore supports [everything go-yaml supports](https://github.com/go-yaml/yaml#compatibility). ## Caveats **Caveat #1:** When using `yaml.Marshal` and `yaml.Unmarshal`, binary data should NOT be preceded with the `!!binary` YAML tag. If you do, go-yaml will convert the binary data from base64 to native binary data, which is not compatible with JSON. You can still use binary in your YAML files though - just store them without the `!!binary` tag and decode the base64 in your code (e.g. in the custom JSON methods `MarshalJSON` and `UnmarshalJSON`). This also has the benefit that your YAML and your JSON binary data will be decoded exactly the same way. As an example: ``` BAD: exampleKey: !!binary gIGC GOOD: exampleKey: gIGC ... and decode the base64 data in your code. ``` **Caveat #2:** When using `YAMLToJSON` directly, maps with keys that are maps will result in an error since this is not supported by JSON. This error will occur in `Unmarshal` as well since you can't unmarshal map keys anyways since struct fields can't be keys. ## Installation and usage To install, run: ``` $ go get github.com/ghodss/yaml ``` And import using: ``` import "github.com/gogf/gf/third/github.com/ghodss/yaml" ``` Usage is very similar to the JSON library: ```go package main import ( "fmt" "github.com/gogf/gf/third/github.com/ghodss/yaml" ) type Person struct { Name string `json:"name"` // Affects YAML field names too. Age int `json:"age"` } func main() { // Marshal a Person struct to YAML. p := Person{"John", 30} y, err := yaml.Marshal(p) if err != nil { fmt.Printf("err: %v\n", err) return } fmt.Println(string(y)) /* Output: age: 30 name: John */ // Unmarshal the YAML back into a Person struct. var p2 Person err = yaml.Unmarshal(y, &p2) if err != nil { fmt.Printf("err: %v\n", err) return } fmt.Println(p2) /* Output: {John 30} */ } ``` `yaml.YAMLToJSON` and `yaml.JSONToYAML` methods are also available: ```go package main import ( "fmt" "github.com/gogf/gf/third/github.com/ghodss/yaml" ) func main() { j := []byte(`{"name": "John", "age": 30}`) y, err := yaml.JSONToYAML(j) if err != nil { fmt.Printf("err: %v\n", err) return } fmt.Println(string(y)) /* Output: name: John age: 30 */ j2, err := yaml.YAMLToJSON(y) if err != nil { fmt.Printf("err: %v\n", err) return } fmt.Println(string(j2)) /* Output: {"age":30,"name":"John"} */ } ```