Add error package and some Matrix errors (#13)

Terse function names are used to make usage not stutter. For example:

```go
err := error.Forbidden("you shall not pass")
```

At the moment they are all the same fundamental `MatrixError` type. This will
be bad if we ever want to `switch` based on the kind of error. I'm hoping we
won't ever need to introspect into errors like this: ideally these errors would
be created purely for immediately being returned in an HTTP response.

`MatrixError` implements the `error` interface.
main
Kegsay 2017-02-20 17:20:49 +00:00 committed by GitHub
parent 434e525ff3
commit 966d3b95b7
2 changed files with 92 additions and 0 deletions

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package jsonerror
import "fmt"
// MatrixError represents the "standard error response" in Matrix.
// http://matrix.org/docs/spec/client_server/r0.2.0.html#api-standards
type MatrixError struct {
ErrCode string `json:"errcode"`
Err string `json:"error"`
}
func (e *MatrixError) Error() string {
return fmt.Sprintf("%s: %s", e.ErrCode, e.Err)
}
// Forbidden is an error when the client tries to access a resource
// they are not allowed to access.
func Forbidden(msg string) *MatrixError {
return &MatrixError{"M_FORBIDDEN", msg}
}
// BadJSON is an error when the client supplies malformed JSON.
func BadJSON(msg string) *MatrixError {
return &MatrixError{"M_BAD_JSON", msg}
}
// NotJSON is an error when the client supplies something that is not JSON
// to a JSON endpoint.
func NotJSON(msg string) *MatrixError {
return &MatrixError{"M_NOT_JSON", msg}
}
// NotFound is an error when the client tries to access an unknown resource.
func NotFound(msg string) *MatrixError {
return &MatrixError{"M_NOT_FOUND", msg}
}
// MissingToken is an error when the client tries to access a resource which
// requires authentication without supplying credentials.
func MissingToken(msg string) *MatrixError {
return &MatrixError{"M_MISSING_TOKEN", msg}
}
// UnknownToken is an error when the client tries to access a resource which
// requires authentication and supplies a valid, but out-of-date token.
func UnknownToken(msg string) *MatrixError {
return &MatrixError{"M_UNKNOWN_TOKEN", msg}
}
// LimitExceededError is a rate-limiting error.
type LimitExceededError struct {
MatrixError
RetryAfterMS int64 `json:"retry_after_ms,omitempty"`
}
// LimitExceeded is an error when the client tries to send events too quickly.
func LimitExceeded(msg string, retryAfterMS int64) *LimitExceededError {
return &LimitExceededError{
MatrixError: MatrixError{"M_LIMIT_EXCEEDED", msg},
RetryAfterMS: retryAfterMS,
}
}

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package jsonerror
import (
"encoding/json"
"testing"
)
func TestLimitExceeded(t *testing.T) {
e := LimitExceeded("too fast", 5000)
jsonBytes, err := json.Marshal(&e)
if err != nil {
t.Fatalf("TestLimitExceeded: Failed to marshal LimitExceeded error. %s", err.Error())
}
want := `{"errcode":"M_LIMIT_EXCEEDED","error":"too fast","retry_after_ms":5000}`
if string(jsonBytes) != want {
t.Errorf("TestLimitExceeded: want %s, got %s", want, string(jsonBytes))
}
}
func TestForbidden(t *testing.T) {
e := Forbidden("you shall not pass")
jsonBytes, err := json.Marshal(&e)
if err != nil {
t.Fatalf("TestForbidden: Failed to marshal Forbidden error. %s", err.Error())
}
want := `{"errcode":"M_FORBIDDEN","error":"you shall not pass"}`
if string(jsonBytes) != want {
t.Errorf("TestForbidden: want %s, got %s", want, string(jsonBytes))
}
}