[feature] More consistent API error handling (#637)

* update templates

* start reworking api error handling

* update template

* return AP status at web endpoint if negotiated

* start making api error handling much more consistent

* update account endpoints to new error handling

* use new api error handling in admin endpoints

* go fmt ./...

* use api error logic in app

* use generic error handling in auth

* don't export generic error handler

* don't defer clearing session

* user nicer error handling on oidc callback handler

* tidy up the sign in handler

* tidy up the token handler

* use nicer error handling in blocksget

* auth emojis endpoint

* fix up remaining api endpoints

* fix whoopsie during login flow

* regenerate swagger docs

* change http error logging to debug

4 files changed, 116 insertions, 81 deletions

diff --git a/internal/web/base.go b/internal/web/base.go
index d203522ae..a8d99619c 100644
--- a/internal/web/base.go
+++ b/internal/web/base.go
@@ -19,6 +19,7 @@
 package web
 
 import (
+	"errors"
 	"fmt"
 	"io/ioutil"
 	"net/http"
@@ -29,6 +30,7 @@ import (
 	"github.com/sirupsen/logrus"
 	"github.com/superseriousbusiness/gotosocial/internal/api"
 	"github.com/superseriousbusiness/gotosocial/internal/config"
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
 	"github.com/superseriousbusiness/gotosocial/internal/processing"
 	"github.com/superseriousbusiness/gotosocial/internal/router"
 	"github.com/superseriousbusiness/gotosocial/internal/uris"
@@ -118,24 +120,6 @@ func (m *Module) baseHandler(c *gin.Context) {
 	})
 }
 
-// NotFoundHandler serves a 404 html page instead of a blank 404 error.
-func (m *Module) NotFoundHandler(c *gin.Context) {
-	l := logrus.WithField("func", "404")
-	l.Trace("serving 404 html")
-
-	host := config.GetHost()
-	instance, err := m.processor.InstanceGet(c.Request.Context(), host)
-	if err != nil {
-		l.Debugf("error getting instance from processor: %s", err)
-		c.JSON(http.StatusInternalServerError, gin.H{"error": "internal server error"})
-		return
-	}
-
-	c.HTML(404, "404.tmpl", gin.H{
-		"instance": instance,
-	})
-}
-
 // Route satisfies the RESTAPIModule interface
 func (m *Module) Route(s router.Router) error {
 	// serve static files from assets dir at /assets
@@ -152,16 +136,18 @@ func (m *Module) Route(s router.Router) error {
 	s.AttachHandler(http.MethodGet, "/", m.baseHandler)
 
 	// serve profile pages at /@username
-	s.AttachHandler(http.MethodGet, profilePath, m.profileTemplateHandler)
+	s.AttachHandler(http.MethodGet, profilePath, m.profileGETHandler)
 
 	// serve statuses
-	s.AttachHandler(http.MethodGet, statusPath, m.threadTemplateHandler)
+	s.AttachHandler(http.MethodGet, statusPath, m.threadGETHandler)
 
 	// serve email confirmation page at /confirm_email?token=whatever
 	s.AttachHandler(http.MethodGet, confirmEmailPath, m.confirmEmailGETHandler)
 
 	// 404 handler
-	s.AttachNoRouteHandler(m.NotFoundHandler)
+	s.AttachNoRouteHandler(func(c *gin.Context) {
+		api.ErrorHandler(c, gtserror.NewErrorNotFound(errors.New(http.StatusText(http.StatusNotFound))), m.processor.InstanceGet)
+	})
 
 	return nil
 }
diff --git a/internal/web/confirmemail.go b/internal/web/confirmemail.go
index 7c8aa464f..58f932bde 100644
--- a/internal/web/confirmemail.go
+++ b/internal/web/confirmemail.go
@@ -19,35 +19,35 @@
 package web
 
 import (
+	"errors"
 	"net/http"
 
 	"github.com/gin-gonic/gin"
-	"github.com/sirupsen/logrus"
+	"github.com/superseriousbusiness/gotosocial/internal/api"
 	"github.com/superseriousbusiness/gotosocial/internal/config"
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
 )
 
 func (m *Module) confirmEmailGETHandler(c *gin.Context) {
+	ctx := c.Request.Context()
+
 	// if there's no token in the query, just serve the 404 web handler
 	token := c.Query(tokenParam)
 	if token == "" {
-		m.NotFoundHandler(c)
+		api.ErrorHandler(c, gtserror.NewErrorNotFound(errors.New(http.StatusText(http.StatusNotFound))), m.processor.InstanceGet)
 		return
 	}
 
-	ctx := c.Request.Context()
-
 	user, errWithCode := m.processor.UserConfirmEmail(ctx, token)
 	if errWithCode != nil {
-		logrus.Debugf("error confirming email: %s", errWithCode.Error())
-		// if something goes wrong, just log it and direct to the 404 handler to not give anything away
-		m.NotFoundHandler(c)
+		api.ErrorHandler(c, errWithCode, m.processor.InstanceGet)
 		return
 	}
 
 	host := config.GetHost()
 	instance, err := m.processor.InstanceGet(ctx, host)
 	if err != nil {
-		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		api.ErrorHandler(c, gtserror.NewErrorInternalError(err), m.processor.InstanceGet)
 		return
 	}
 
diff --git a/internal/web/profile.go b/internal/web/profile.go
index 3155c022d..051d55d28 100644
--- a/internal/web/profile.go
+++ b/internal/web/profile.go
@@ -21,59 +21,60 @@ package web
 import (
 	"context"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"math/rand"
 	"net/http"
+	"strings"
 
 	"github.com/gin-gonic/gin"
-	"github.com/sirupsen/logrus"
 	"github.com/superseriousbusiness/gotosocial/internal/ap"
 	"github.com/superseriousbusiness/gotosocial/internal/api"
 	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
 	"github.com/superseriousbusiness/gotosocial/internal/config"
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
 	"github.com/superseriousbusiness/gotosocial/internal/oauth"
 )
 
-func (m *Module) profileTemplateHandler(c *gin.Context) {
-	l := logrus.WithField("func", "profileTemplateHandler")
-	l.Trace("rendering profile template")
+func (m *Module) profileGETHandler(c *gin.Context) {
 	ctx := c.Request.Context()
 
-	username := c.Param(usernameKey)
+	authed, err := oauth.Authed(c, false, false, false, false)
+	if err != nil {
+		api.ErrorHandler(c, gtserror.NewErrorUnauthorized(err, err.Error()), m.processor.InstanceGet)
+		return
+	}
+
+	// usernames on our instance will always be lowercase
+	username := strings.ToLower(c.Param(usernameKey))
 	if username == "" {
-		c.JSON(http.StatusBadRequest, gin.H{"error": "no account username specified"})
+		err := errors.New("no account username specified")
+		api.ErrorHandler(c, gtserror.NewErrorBadRequest(err, err.Error()), m.processor.InstanceGet)
 		return
 	}
 
-	authed, err := oauth.Authed(c, false, false, false, false)
+	host := config.GetHost()
+	instance, err := m.processor.InstanceGet(ctx, host)
 	if err != nil {
-		l.Errorf("error authing profile GET request: %s", err)
-		c.JSON(http.StatusInternalServerError, gin.H{"error": "internal server error"})
+		api.ErrorHandler(c, gtserror.NewErrorInternalError(err), m.processor.InstanceGet)
 		return
 	}
 
-	instance, errWithCode := m.processor.InstanceGet(ctx, config.GetHost())
-	if errWithCode != nil {
-		l.Debugf("error getting instance from processor: %s", errWithCode.Error())
-		c.JSON(errWithCode.Code(), gin.H{"error": errWithCode.Safe()})
-		return
+	instanceGet := func(ctx context.Context, domain string) (*apimodel.Instance, gtserror.WithCode) {
+		return instance, nil
 	}
 
 	account, errWithCode := m.processor.AccountGetLocalByUsername(ctx, authed, username)
 	if errWithCode != nil {
-		l.Debugf("error getting account from processor: %s", errWithCode.Error())
-		if errWithCode.Code() == http.StatusNotFound {
-			m.NotFoundHandler(c)
-			return
-		}
-		c.JSON(errWithCode.Code(), gin.H{"error": errWithCode.Safe()})
+		api.ErrorHandler(c, errWithCode, instanceGet)
 		return
 	}
 
-	// if we're getting an AP request on this endpoint we should render the account's AP representation instead
+	// if we're getting an AP request on this endpoint we
+	// should render the account's AP representation instead
 	accept := c.NegotiateFormat(string(api.TextHTML), string(api.AppActivityJSON), string(api.AppActivityLDJSON))
 	if accept == string(api.AppActivityJSON) || accept == string(api.AppActivityLDJSON) {
-		m.returnAPRepresentation(ctx, c, username, accept)
+		m.returnAPProfile(ctx, c, username, accept)
 		return
 	}
 
@@ -82,8 +83,7 @@ func (m *Module) profileTemplateHandler(c *gin.Context) {
 	// with or without media
 	statusResp, errWithCode := m.processor.AccountStatusesGet(ctx, authed, account.ID, 10, true, true, "", "", false, false, true)
 	if errWithCode != nil {
-		l.Debugf("error getting statuses from processor: %s", errWithCode.Error())
-		c.JSON(errWithCode.Code(), gin.H{"error": errWithCode.Safe()})
+		api.ErrorHandler(c, errWithCode, instanceGet)
 		return
 	}
 
@@ -114,7 +114,7 @@ func (m *Module) profileTemplateHandler(c *gin.Context) {
 	})
 }
 
-func (m *Module) returnAPRepresentation(ctx context.Context, c *gin.Context, username string, accept string) {
+func (m *Module) returnAPProfile(ctx context.Context, c *gin.Context, username string, accept string) {
 	verifier, signed := c.Get(string(ap.ContextRequestingPublicKeyVerifier))
 	if signed {
 		ctx = context.WithValue(ctx, ap.ContextRequestingPublicKeyVerifier, verifier)
@@ -125,17 +125,16 @@ func (m *Module) returnAPRepresentation(ctx context.Context, c *gin.Context, use
 		ctx = context.WithValue(ctx, ap.ContextRequestingPublicKeySignature, signature)
 	}
 
-	user, errWithCode := m.processor.GetFediUser(ctx, username, c.Request.URL) // GetFediUser handles auth as well
+	user, errWithCode := m.processor.GetFediUser(ctx, username, c.Request.URL)
 	if errWithCode != nil {
-		logrus.Infof(errWithCode.Error())
-		c.JSON(errWithCode.Code(), gin.H{"error": errWithCode.Safe()})
+		api.ErrorHandler(c, errWithCode, m.processor.InstanceGet)
 		return
 	}
 
 	b, mErr := json.Marshal(user)
 	if mErr != nil {
 		err := fmt.Errorf("could not marshal json: %s", mErr)
-		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		api.ErrorHandler(c, gtserror.NewErrorInternalError(err), m.processor.InstanceGet)
 		return
 	}
 
diff --git a/internal/web/thread.go b/internal/web/thread.go
index 3a9839281..5e953ee06 100644
--- a/internal/web/thread.go
+++ b/internal/web/thread.go
@@ -19,65 +19,88 @@
 package web
 
 import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
 	"net/http"
 	"strings"
 
-	"github.com/sirupsen/logrus"
-
 	"github.com/gin-gonic/gin"
+	"github.com/superseriousbusiness/gotosocial/internal/ap"
+	"github.com/superseriousbusiness/gotosocial/internal/api"
+	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
 	"github.com/superseriousbusiness/gotosocial/internal/config"
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
 	"github.com/superseriousbusiness/gotosocial/internal/oauth"
 )
 
-func (m *Module) threadTemplateHandler(c *gin.Context) {
-	l := logrus.WithField("func", "threadTemplateGET")
-	l.Trace("rendering thread template")
-
+func (m *Module) threadGETHandler(c *gin.Context) {
 	ctx := c.Request.Context()
 
+	authed, err := oauth.Authed(c, false, false, false, false)
+	if err != nil {
+		api.ErrorHandler(c, gtserror.NewErrorUnauthorized(err, err.Error()), m.processor.InstanceGet)
+		return
+	}
+
 	// usernames on our instance will always be lowercase
 	username := strings.ToLower(c.Param(usernameKey))
 	if username == "" {
-		c.JSON(http.StatusBadRequest, gin.H{"error": "no account username specified"})
+		err := errors.New("no account username specified")
+		api.ErrorHandler(c, gtserror.NewErrorBadRequest(err, err.Error()), m.processor.InstanceGet)
 		return
 	}
 
 	// status ids will always be uppercase
 	statusID := strings.ToUpper(c.Param(statusIDKey))
 	if statusID == "" {
-		c.JSON(http.StatusBadRequest, gin.H{"error": "no status id specified"})
+		err := errors.New("no status id specified")
+		api.ErrorHandler(c, gtserror.NewErrorBadRequest(err, err.Error()), m.processor.InstanceGet)
 		return
 	}
 
-	authed, err := oauth.Authed(c, false, false, false, false)
+	host := config.GetHost()
+	instance, err := m.processor.InstanceGet(ctx, host)
 	if err != nil {
-		l.Errorf("error authing status GET request: %s", err)
-		c.JSON(http.StatusBadRequest, gin.H{"error": "status not found"})
+		api.ErrorHandler(c, gtserror.NewErrorInternalError(err), m.processor.InstanceGet)
 		return
 	}
 
-	host := config.GetHost()
-	instance, err := m.processor.InstanceGet(ctx, host)
-	if err != nil {
-		l.Debugf("error getting instance from processor: %s", err)
-		c.JSON(http.StatusInternalServerError, gin.H{"error": "internal server error"})
+	instanceGet := func(ctx context.Context, domain string) (*apimodel.Instance, gtserror.WithCode) {
+		return instance, nil
+	}
+
+	// do this check to make sure the status is actually from a local account,
+	// we shouldn't render threads from statuses that don't belong to us!
+	if _, errWithCode := m.processor.AccountGetLocalByUsername(ctx, authed, username); errWithCode != nil {
+		api.ErrorHandler(c, errWithCode, instanceGet)
 		return
 	}
 
-	status, err := m.processor.StatusGet(ctx, authed, statusID)
-	if err != nil {
-		c.JSON(http.StatusBadRequest, gin.H{"error": "status not found"})
+	status, errWithCode := m.processor.StatusGet(ctx, authed, statusID)
+	if errWithCode != nil {
+		api.ErrorHandler(c, errWithCode, instanceGet)
 		return
 	}
 
 	if !strings.EqualFold(username, status.Account.Username) {
-		c.JSON(http.StatusBadRequest, gin.H{"error": "status not found"})
+		err := gtserror.NewErrorNotFound(errors.New("path username not equal to status author username"))
+		api.ErrorHandler(c, gtserror.NewErrorNotFound(err), instanceGet)
 		return
 	}
 
-	context, err := m.processor.StatusGetContext(ctx, authed, statusID)
-	if err != nil {
-		c.JSON(http.StatusBadRequest, gin.H{"error": "status not found"})
+	// if we're getting an AP request on this endpoint we
+	// should render the status's AP representation instead
+	accept := c.NegotiateFormat(string(api.TextHTML), string(api.AppActivityJSON), string(api.AppActivityLDJSON))
+	if accept == string(api.AppActivityJSON) || accept == string(api.AppActivityLDJSON) {
+		m.returnAPStatus(ctx, c, username, statusID, accept)
+		return
+	}
+
+	context, errWithCode := m.processor.StatusGetContext(ctx, authed, statusID)
+	if errWithCode != nil {
+		api.ErrorHandler(c, errWithCode, instanceGet)
 		return
 	}
 
@@ -88,3 +111,30 @@ func (m *Module) threadTemplateHandler(c *gin.Context) {
 		"stylesheets": []string{"/assets/Fork-Awesome/css/fork-awesome.min.css", "/assets/status.css"},
 	})
 }
+
+func (m *Module) returnAPStatus(ctx context.Context, c *gin.Context, username string, statusID string, accept string) {
+	verifier, signed := c.Get(string(ap.ContextRequestingPublicKeyVerifier))
+	if signed {
+		ctx = context.WithValue(ctx, ap.ContextRequestingPublicKeyVerifier, verifier)
+	}
+
+	signature, signed := c.Get(string(ap.ContextRequestingPublicKeySignature))
+	if signed {
+		ctx = context.WithValue(ctx, ap.ContextRequestingPublicKeySignature, signature)
+	}
+
+	status, errWithCode := m.processor.GetFediStatus(ctx, username, statusID, c.Request.URL)
+	if errWithCode != nil {
+		api.ErrorHandler(c, errWithCode, m.processor.InstanceGet)
+		return
+	}
+
+	b, mErr := json.Marshal(status)
+	if mErr != nil {
+		err := fmt.Errorf("could not marshal json: %s", mErr)
+		api.ErrorHandler(c, gtserror.NewErrorInternalError(err), m.processor.InstanceGet)
+		return
+	}
+
+	c.Data(http.StatusOK, accept, b)
+}