Timeline manager (#40)

* start messing about with timeline manager

* i have no idea what i'm doing

* i continue to not know what i'm doing

* it's coming along

* bit more progress

* update timeline with new posts as they come in

* lint and fmt

* Select accounts where empty string

* restructure a bunch, get unfaves working

* moving stuff around

* federate status deletes properly

* mention regex better but not 100% there

* fix regex

* some more hacking away at the timeline code phew

* fix up some little things

* i can't even

* more timeline stuff

* move to ulid

* fiddley

* some lil fixes for kibou compatibility

* timelines working pretty alright!

* tidy + lint

internal/gtserror/withcode.go

@@ -0,0 +1,124 @@
+/*
+   GoToSocial
+   Copyright (C) 2021 GoToSocial Authors admin@gotosocial.org
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package gtserror
+
+import (
+	"errors"
+	"net/http"
+	"strings"
+)
+
+// WithCode wraps an internal error with an http code, and a 'safe' version of
+// the error that can be served to clients without revealing internal business logic.
+//
+// A typical use of this error would be to first log the Original error, then return
+// the Safe error and the StatusCode to an API caller.
+type WithCode interface {
+	// Error returns the original internal error for debugging within the GoToSocial logs.
+	// This should *NEVER* be returned to a client as it may contain sensitive information.
+	Error() string
+	// Safe returns the API-safe version of the error for serialization towards a client.
+	// There's not much point logging this internally because it won't contain much helpful information.
+	Safe() string
+	//  Code returns the status code for serving to a client.
+	Code() int
+}
+
+type withCode struct {
+	original error
+	safe     error
+	code     int
+}
+
+func (e withCode) Error() string {
+	return e.original.Error()
+}
+
+func (e withCode) Safe() string {
+	return e.safe.Error()
+}
+
+func (e withCode) Code() int {
+	return e.code
+}
+
+// NewErrorBadRequest returns an ErrorWithCode 400 with the given original error and optional help text.
+func NewErrorBadRequest(original error, helpText ...string) WithCode {
+	safe := "bad request"
+	if helpText != nil {
+		safe = safe + ": " + strings.Join(helpText, ": ")
+	}
+	return withCode{
+		original: original,
+		safe:     errors.New(safe),
+		code:     http.StatusBadRequest,
+	}
+}
+
+// NewErrorNotAuthorized returns an ErrorWithCode 401 with the given original error and optional help text.
+func NewErrorNotAuthorized(original error, helpText ...string) WithCode {
+	safe := "not authorized"
+	if helpText != nil {
+		safe = safe + ": " + strings.Join(helpText, ": ")
+	}
+	return withCode{
+		original: original,
+		safe:     errors.New(safe),
+		code:     http.StatusUnauthorized,
+	}
+}
+
+// NewErrorForbidden returns an ErrorWithCode 403 with the given original error and optional help text.
+func NewErrorForbidden(original error, helpText ...string) WithCode {
+	safe := "forbidden"
+	if helpText != nil {
+		safe = safe + ": " + strings.Join(helpText, ": ")
+	}
+	return withCode{
+		original: original,
+		safe:     errors.New(safe),
+		code:     http.StatusForbidden,
+	}
+}
+
+// NewErrorNotFound returns an ErrorWithCode 404 with the given original error and optional help text.
+func NewErrorNotFound(original error, helpText ...string) WithCode {
+	safe := "404 not found"
+	if helpText != nil {
+		safe = safe + ": " + strings.Join(helpText, ": ")
+	}
+	return withCode{
+		original: original,
+		safe:     errors.New(safe),
+		code:     http.StatusNotFound,
+	}
+}
+
+// NewErrorInternalError returns an ErrorWithCode 500 with the given original error and optional help text.
+func NewErrorInternalError(original error, helpText ...string) WithCode {
+	safe := "internal server error"
+	if helpText != nil {
+		safe = safe + ": " + strings.Join(helpText, ": ")
+	}
+	return withCode{
+		original: original,
+		safe:     errors.New(safe),
+		code:     http.StatusInternalServerError,
+	}
+}