[chore] Rationalize HTTP return codes for fedi endpoints, other tidying up (#4503)

# Description

> If this is a code change, please include a summary of what you've coded, and link to the issue(s) it closes/implements.
>
> If this is a documentation change, please briefly describe what you've changed and why.

This pull request does some refactoring of the fedi API endpoints and processing functions, and the authenticate + pub key deref functions, to try to return fewer silly HTTP codes like 410 Gone (when a *remote* account is gone, not a local one), and 500 errors where something isn't really an error.

Also does some general tidying up and renaming for consistency.

## Checklist

Please put an x inside each checkbox to indicate that you've read and followed it: `[ ]` -> `[x]`

If this is a documentation change, only the first checkbox must be filled (you can delete the others if you want).

- [x] I/we have read the [GoToSocial contribution guidelines](https://codeberg.org/superseriousbusiness/gotosocial/src/branch/main/CONTRIBUTING.md).
- [x] I/we have discussed the proposed changes already, either in an issue on the repository, or in the Matrix chat.
- [x] I/we have not leveraged AI to create the proposed changes.
- [x] I/we have performed a self-review of added code.
- [x] I/we have written code that is legible and maintainable by others.
- [x] I/we have commented the added code, particularly in hard-to-understand areas.
- [ ] I/we have made any necessary changes to documentation.
- [ ] I/we have added tests that cover new code.
- [x] I/we have run tests and they pass locally with the changes.
- [x] I/we have run `go fmt ./...` and `golangci-lint run`.

Reviewed-on: https://codeberg.org/superseriousbusiness/gotosocial/pulls/4503
Co-authored-by: tobi <tobi.smethurst@protonmail.com>
Co-committed-by: tobi <tobi.smethurst@protonmail.com>

3 files changed, 7 insertions, 10 deletions

diff --git a/internal/api/activitypub/emoji/emoji.go b/internal/api/activitypub/emoji/emoji.go
index 361a3bbc7..e218af9ad 100644
--- a/internal/api/activitypub/emoji/emoji.go
+++ b/internal/api/activitypub/emoji/emoji.go
@@ -20,16 +20,12 @@ package emoji
 import (
 	"net/http"
 
+	apiutil "code.superseriousbusiness.org/gotosocial/internal/api/util"
 	"code.superseriousbusiness.org/gotosocial/internal/processing"
 	"github.com/gin-gonic/gin"
 )
 
-const (
-	// EmojiIDKey is for emoji IDs
-	EmojiIDKey = "id"
-	// EmojiBasePath is the base path for serving AP Emojis, minus the "emoji" prefix
-	EmojiWithIDPath = "/:" + EmojiIDKey
-)
+const EmojiWithIDPath = "/:" + apiutil.IDKey
 
 type Module struct {
 	processor *processing.Processor
diff --git a/internal/api/activitypub/emoji/emojiget.go b/internal/api/activitypub/emoji/emojiget.go
index cc0049f89..fc6740c9b 100644
--- a/internal/api/activitypub/emoji/emojiget.go
+++ b/internal/api/activitypub/emoji/emojiget.go
@@ -28,8 +28,8 @@ import (
 )
 
 func (m *Module) EmojiGetHandler(c *gin.Context) {
-	requestedEmojiID := strings.ToUpper(c.Param(EmojiIDKey))
-	if requestedEmojiID == "" {
+	emojiID := strings.ToUpper(c.Param(apiutil.IDKey))
+	if emojiID == "" {
 		err := errors.New("no emoji id specified in request")
 		apiutil.ErrorHandler(c, gtserror.NewErrorBadRequest(err, err.Error()), m.processor.InstanceGetV1)
 		return
@@ -41,7 +41,7 @@ func (m *Module) EmojiGetHandler(c *gin.Context) {
 		return
 	}
 
-	resp, errWithCode := m.processor.Fedi().EmojiGet(c.Request.Context(), requestedEmojiID)
+	resp, errWithCode := m.processor.Fedi().EmojiGet(c.Request.Context(), emojiID)
 	if errWithCode != nil {
 		apiutil.ErrorHandler(c, errWithCode, m.processor.InstanceGetV1)
 		return
diff --git a/internal/api/activitypub/emoji/emojiget_test.go b/internal/api/activitypub/emoji/emojiget_test.go
index 071cb80b6..9cc13f978 100644
--- a/internal/api/activitypub/emoji/emojiget_test.go
+++ b/internal/api/activitypub/emoji/emojiget_test.go
@@ -25,6 +25,7 @@ import (
 
 	"code.superseriousbusiness.org/gotosocial/internal/admin"
 	"code.superseriousbusiness.org/gotosocial/internal/api/activitypub/emoji"
+	apiutil "code.superseriousbusiness.org/gotosocial/internal/api/util"
 	"code.superseriousbusiness.org/gotosocial/internal/db"
 	"code.superseriousbusiness.org/gotosocial/internal/email"
 	"code.superseriousbusiness.org/gotosocial/internal/federation"
@@ -122,7 +123,7 @@ func (suite *EmojiGetTestSuite) TestGetEmoji() {
 	// but because we're calling the function directly, we need to set them manually.
 	ctx.Params = gin.Params{
 		gin.Param{
-			Key:   emoji.EmojiIDKey,
+			Key:   apiutil.IDKey,
 			Value: targetEmoji.ID,
 		},
 	}