89 lines
2.1 KiB
Go
89 lines
2.1 KiB
Go
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package hal
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import (
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"encoding/json"
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"github.com/raff/halgo"
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)
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// Resource is a simple HAL resource envelope that uses halgo.Link for links.
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type Resource struct {
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Links map[string]halgo.Link `json:"_links,omitempty"`
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Embedded map[string]interface{} `json:"_embedded,omitempty"`
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// State holds arbitrary resource state merged at top-level when marshaled
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State map[string]interface{} `json:"-"`
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}
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// New creates a new HAL resource with a self link.
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func New(selfHref string) *Resource {
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r := &Resource{
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Links: map[string]halgo.Link{},
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Embedded: map[string]interface{}{},
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State: map[string]interface{}{},
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}
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if selfHref != "" {
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r.AddLink("self", halgo.Link{Href: selfHref})
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}
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return r
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}
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// AddLink adds a link with the given rel.
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func (r *Resource) AddLink(rel string, link halgo.Link) {
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if r.Links == nil {
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r.Links = map[string]halgo.Link{}
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}
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r.Links[rel] = link
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}
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// AddCurie adds a CURIE link for the sakila namespace.
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// Note: HAL recommends an array for the "curies" rel. This implementation uses a single link
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// due to the underlying link map being single-valued per rel. Most clients accept this form.
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func (r *Resource) AddCurie() {
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r.AddLink("curies", halgo.Link{
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Href: "/rels/{rel}",
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Templated: true,
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Name: "sakila",
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})
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}
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// Embed sets an embedded payload under the rel.
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func (r *Resource) Embed(rel string, v interface{}) {
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if r.Embedded == nil {
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r.Embedded = map[string]interface{}{}
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}
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r.Embedded[rel] = v
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}
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// SetState sets or merges state fields.
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func (r *Resource) SetState(obj interface{}) {
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switch m := obj.(type) {
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case map[string]interface{}:
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for k, v := range m {
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r.State[k] = v
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}
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default:
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// marshal into map and merge
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b, _ := json.Marshal(obj)
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var mm map[string]interface{}
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_ = json.Unmarshal(b, &mm)
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for k, v := range mm {
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r.State[k] = v
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}
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}
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}
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// MarshalJSON merges State with _links and _embedded following HAL conventions.
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func (r *Resource) MarshalJSON() ([]byte, error) {
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m := map[string]interface{}{}
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for k, v := range r.State {
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m[k] = v
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}
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if len(r.Links) > 0 {
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m["_links"] = r.Links
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}
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if len(r.Embedded) > 0 {
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m["_embedded"] = r.Embedded
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}
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return json.Marshal(m)
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}
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