97 lines
2.5 KiB
Go
97 lines
2.5 KiB
Go
package profilefed
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import (
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"crypto/ed25519"
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"encoding/base64"
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"encoding/json"
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"errors"
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"net/http"
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"slices"
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"strings"
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)
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// ErrDescriptorNotFound should be returned
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var ErrDescriptorNotFound = errors.New("descriptor not found")
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// AddExtra is a convenience function that adds an extra data object to the descriptor.
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// It defines any undefined namespaces and marshals the data parameter into JSON.
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func (d *Descriptor) AddExtra(namespace, etype string, data any) error {
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// Remove the fragment from the namespace URL if it exists
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urlStr, _, _ := strings.Cut(namespace, "#")
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if !slices.Contains(d.Namespaces, urlStr) {
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d.Namespaces = append(d.Namespaces, urlStr)
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}
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msg, err := json.Marshal(data)
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if err != nil {
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return err
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}
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d.Extra = append(d.Extra, Extra{
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Namespace: namespace,
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Type: etype,
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Data: msg,
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})
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return nil
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}
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type Handler struct {
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// PrivateKey contains the server's Ed25519 private key for signing responses
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PrivateKey ed25519.PrivateKey
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// AllDescriptorsFunc should return all the profile descriptors known to the server.
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// If no matching descriptors can be found, AllDescriptorsFunc should reutnr
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// [ErrDescriptorNotFound].
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AllDescriptorsFunc func(req *http.Request) (map[string]*Descriptor, error)
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// DescriptorFunc should return a single descriptor. Make sure to check the `id`
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// query parameter if your user has several descriptors available. If a matching
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// descriptor cannot be found, DescriptorFunc should return [ErrDescriptorNotFound].
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DescriptorFunc func(req *http.Request) (*Descriptor, error)
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// ErrorHandler is called whenever an error is encountered.
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ErrorHandler func(err error, res http.ResponseWriter)
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}
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// ServeHTTP implements the [http.Handler] interface
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func (h Handler) ServeHTTP(res http.ResponseWriter, req *http.Request) {
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var data []byte
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if req.URL.Query().Get("all") == "1" {
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descriptors, err := h.AllDescriptorsFunc(req)
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if err != nil {
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h.ErrorHandler(err, res)
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return
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}
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data, err = json.Marshal(descriptors)
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if err != nil {
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h.ErrorHandler(err, res)
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return
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}
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} else {
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descriptor, err := h.DescriptorFunc(req)
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if err != nil {
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h.ErrorHandler(err, res)
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return
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}
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data, err = json.Marshal(descriptor)
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if err != nil {
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h.ErrorHandler(err, res)
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return
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}
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}
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sig := ed25519.Sign(h.PrivateKey, data)
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res.Header().Set("X-ProfileFed-Sig", base64.StdEncoding.EncodeToString(sig))
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res.Header().Set("Content-Type", "application/x-pfd+json")
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_, err := res.Write(data)
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if err != nil {
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h.ErrorHandler(err, res)
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return
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}
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}
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