ntfy/server/server_matrix.go
2023-02-24 22:07:18 -05:00

181 lines
7.2 KiB
Go

package server
import (
"bytes"
"encoding/json"
"fmt"
"heckel.io/ntfy/util"
"io"
"net/http"
"strings"
)
// Matrix Push Gateway / UnifiedPush / ntfy integration:
//
// ntfy implements a Matrix Push Gateway (as defined in https://spec.matrix.org/v1.2/push-gateway-api/),
// in combination with UnifiedPush as the Provider Push Protocol (as defined in https://unifiedpush.org/developers/gateway/).
//
// In the picture below, ntfy is the Push Gateway (mostly in this file), as well as the Push Provider (ntfy's
// main functionality). UnifiedPush is the Provider Push Protocol, as implemented by the ntfy server and the
// ntfy Android app.
//
// +--------------------+ +-------------------+
// Matrix HTTP | | | |
// Notification Protocol | App Developer | | Device Vendor |
// | | | |
// +-------------------+ | +----------------+ | | +---------------+ |
// | | | | | | | | | |
// | Matrix homeserver +-----> Push Gateway +------> Push Provider | |
// | | | | | | | | | |
// +-^-----------------+ | +----------------+ | | +----+----------+ |
// | | | | | |
// Matrix | | | | | |
// Client/Server API + | | | | |
// | | +--------------------+ +-------------------+
// | +--+-+ |
// | | <-------------------------------------------+
// +---+ |
// | | Provider Push Protocol
// +----+
//
// Mobile Device or Client
//
// matrixRequest represents a Matrix message, as it is sent to a Push Gateway (as per
// this spec: https://spec.matrix.org/v1.2/push-gateway-api/).
//
// From the message, we only require the "pushkey", as it represents our target topic URL.
// A message may look like this (excerpt):
//
// {
// "notification": {
// "devices": [
// {
// "pushkey": "https://ntfy.sh/upDAHJKFFDFD?up=1",
// ...
// }
// ]
// }
// }
type matrixRequest struct {
Notification *struct {
Devices []*struct {
PushKey string `json:"pushkey"`
} `json:"devices"`
} `json:"notification"`
}
// matrixResponse represents the response to a Matrix push gateway message, as defined
// in the spec (https://spec.matrix.org/v1.2/push-gateway-api/).
type matrixResponse struct {
Rejected []string `json:"rejected"`
}
// errMatrix represents an error when handing Matrix gateway messages
//
// If the pushKey is set, the app server will remove it and will never send messages using the same
// push key again, until the user repairs it.
type errMatrix struct {
pushKey string
err error
}
func (e errMatrix) Error() string {
if e.err != nil {
return fmt.Sprintf("message with push key %s rejected: %s", e.pushKey, e.err.Error())
}
return fmt.Sprintf("message with push key %s rejected", e.pushKey)
}
const (
// matrixPushKeyHeader is a header that's used internally to pass the Matrix push key (from the matrixRequest)
// along with the request. The push key is only used if an error occurs down the line.
matrixPushKeyHeader = "X-Matrix-Pushkey"
)
// newRequestFromMatrixJSON reads the request body as a Matrix JSON message, parses the "pushkey", and creates a new
// HTTP request that looks like a normal ntfy request from it.
//
// It basically converts a Matrix push gatewqy request:
//
// POST /_matrix/push/v1/notify HTTP/1.1
// { "notification": { "devices": [ { "pushkey": "https://ntfy.sh/upDAHJKFFDFD?up=1", ... } ] } }
//
// to a ntfy request, looking like this:
//
// POST /upDAHJKFFDFD?up=1 HTTP/1.1
// { "notification": { "devices": [ { "pushkey": "https://ntfy.sh/upDAHJKFFDFD?up=1", ... } ] } }
func newRequestFromMatrixJSON(r *http.Request, baseURL string, messageLimit int) (*http.Request, error) {
if baseURL == "" {
return nil, errHTTPInternalErrorMissingBaseURL
}
body, err := util.Peek(r.Body, messageLimit)
if err != nil {
return nil, err
}
defer r.Body.Close()
if body.LimitReached {
return nil, errHTTPEntityTooLargeMatrixRequest
}
var m matrixRequest
if err := json.Unmarshal(body.PeekedBytes, &m); err != nil {
return nil, errHTTPBadRequestMatrixMessageInvalid
} else if m.Notification == nil || len(m.Notification.Devices) == 0 || m.Notification.Devices[0].PushKey == "" {
return nil, errHTTPBadRequestMatrixMessageInvalid
}
pushKey := m.Notification.Devices[0].PushKey // We ignore other devices for now, see discussion in #316
if !strings.HasPrefix(pushKey, baseURL+"/") {
return nil, &errMatrix{pushKey: pushKey, err: wrapErrHTTP(errHTTPBadRequestMatrixPushkeyBaseURLMismatch, "received push key: %s, configured base URL: %s", pushKey, baseURL)}
}
newRequest, err := http.NewRequest(http.MethodPost, pushKey, io.NopCloser(bytes.NewReader(body.PeekedBytes)))
if err != nil {
return nil, &errMatrix{pushKey: pushKey, err: err}
}
newRequest.RemoteAddr = r.RemoteAddr // Not strictly necessary, since visitor was already extracted
if r.Header.Get("X-Forwarded-For") != "" {
newRequest.Header.Set("X-Forwarded-For", r.Header.Get("X-Forwarded-For"))
}
newRequest.Header.Set(matrixPushKeyHeader, pushKey)
return newRequest, nil
}
// writeMatrixDiscoveryResponse writes the UnifiedPush Matrix Gateway Discovery response to the given http.ResponseWriter,
// as per the spec (https://unifiedpush.org/developers/gateway/).
func writeMatrixDiscoveryResponse(w http.ResponseWriter) error {
w.Header().Set("Content-Type", "application/json")
_, err := io.WriteString(w, `{"unifiedpush":{"gateway":"matrix"}}`+"\n")
return err
}
// writeMatrixError logs and writes the errMatrix to the given http.ResponseWriter as a matrixResponse
func writeMatrixError(w http.ResponseWriter, r *http.Request, v *visitor, err *errMatrix) error {
logvr(v, r).Tag(tagMatrix).Err(err).Debug("Matrix gateway error")
if httpErr, ok := err.err.(*errHTTP); ok {
w.Header().Set("X-Ntfy-Error-Code", fmt.Sprintf("%d", httpErr.Code))
w.Header().Set("X-Ntfy-Error-Message", httpErr.Message)
w.WriteHeader(httpErr.HTTPCode)
}
return writeMatrixResponse(w, err.pushKey)
}
// writeMatrixSuccess writes a successful matrixResponse (no rejected push key) to the given http.ResponseWriter
func writeMatrixSuccess(w http.ResponseWriter) error {
return writeMatrixResponse(w, "")
}
// writeMatrixResponse writes a matrixResponse to the given http.ResponseWriter, as defined in
// the spec (https://spec.matrix.org/v1.2/push-gateway-api/)
func writeMatrixResponse(w http.ResponseWriter, rejectedPushKey string) error {
rejected := make([]string, 0)
if rejectedPushKey != "" {
rejected = append(rejected, rejectedPushKey)
}
response := &matrixResponse{
Rejected: rejected,
}
w.Header().Set("Content-Type", "application/json")
if err := json.NewEncoder(w).Encode(response); err != nil {
return err
}
return nil
}