[feature] Object store custom URL (S3) (#3046)

* tweaks

* boobs

* fix variable name + typo

---------

Co-authored-by: tobi <tobi.smethurst@protonmail.com>

internal/config/config.go

@@ -110,6 +110,7 @@ type Configuration struct {
 	StorageS3UseSSL      bool   `name:"storage-s3-use-ssl" usage:"Use SSL for S3 connections. Only set this to 'false' when testing locally"`
 	StorageS3BucketName  string `name:"storage-s3-bucket" usage:"Place blobs in this bucket"`
 	StorageS3Proxy       bool   `name:"storage-s3-proxy" usage:"Proxy S3 contents through GoToSocial instead of redirecting to a presigned URL"`
+	StorageS3RedirectURL string `name:"storage-s3-redirect-url" usage:"Custom URL to use for redirecting S3 media links. If set, this will be used instead of the S3 bucket URL."`
 
 	StatusesMaxChars           int `name:"statuses-max-chars" usage:"Max permitted characters for posted statuses, including content warning"`
 	StatusesPollMaxOptions     int `name:"statuses-poll-max-options" usage:"Max amount of options permitted on a poll"`

internal/config/defaults.go

@@ -85,6 +85,7 @@ var Defaults = Configuration{
 	StorageLocalBasePath: "/gotosocial/storage",
 	StorageS3UseSSL:      true,
 	StorageS3Proxy:       false,
+	StorageS3RedirectURL: "",
 
 	StatusesMaxChars:           5000,
 	StatusesPollMaxOptions:     6,

internal/config/helpers.gen.go

@@ -1500,6 +1500,31 @@ func GetStorageS3Proxy() bool { return global.GetStorageS3Proxy() }
 // SetStorageS3Proxy safely sets the value for global configuration 'StorageS3Proxy' field
 func SetStorageS3Proxy(v bool) { global.SetStorageS3Proxy(v) }
 
+// GetStorageS3RedirectURL safely fetches the Configuration value for state's 'StorageS3RedirectURL' field
+func (st *ConfigState) GetStorageS3RedirectURL() (v string) {
+	st.mutex.RLock()
+	v = st.config.StorageS3RedirectURL
+	st.mutex.RUnlock()
+	return
+}
+
+// SetStorageS3RedirectURL safely sets the Configuration value for state's 'StorageS3RedirectURL' field
+func (st *ConfigState) SetStorageS3RedirectURL(v string) {
+	st.mutex.Lock()
+	defer st.mutex.Unlock()
+	st.config.StorageS3RedirectURL = v
+	st.reloadToViper()
+}
+
+// StorageS3RedirectURLFlag returns the flag name for the 'StorageS3RedirectURL' field
+func StorageS3RedirectURLFlag() string { return "storage-s3-redirect-url" }
+
+// GetStorageS3RedirectURL safely fetches the value for global configuration 'StorageS3RedirectURL' field
+func GetStorageS3RedirectURL() string { return global.GetStorageS3RedirectURL() }
+
+// SetStorageS3RedirectURL safely sets the value for global configuration 'StorageS3RedirectURL' field
+func SetStorageS3RedirectURL(v string) { global.SetStorageS3RedirectURL(v) }
+
 // GetStatusesMaxChars safely fetches the Configuration value for state's 'StatusesMaxChars' field
 func (st *ConfigState) GetStatusesMaxChars() (v int) {
 	st.mutex.RLock()

internal/config/validate.go

@@ -19,6 +19,8 @@ package config
 
 import (
 	"fmt"
+	"net/url"
+	"strings"
 
 	"github.com/miekg/dns"
 	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
@@ -118,6 +120,28 @@ func Validate() error {
 		errf("%s must be set", WebAssetBaseDirFlag())
 	}
 
+	// `storage-s3-redirect-url`
+	if s3RedirectURL := GetStorageS3RedirectURL(); s3RedirectURL != "" {
+		if strings.HasSuffix(s3RedirectURL, "/") {
+			errf(
+				"%s must not end with a trailing slash",
+				StorageS3RedirectURLFlag(),
+			)
+		}
+
+		if url, err := url.Parse(s3RedirectURL); err != nil {
+			errf(
+				"%s invalid: %w",
+				StorageS3RedirectURLFlag(), err,
+			)
+		} else if url.Scheme != "https" && url.Scheme != "http" {
+			errf(
+				"%s scheme must be https or http",
+				StorageS3RedirectURLFlag(),
+			)
+		}
+	}
+
 	// Custom / LE TLS settings.
 	//
 	// Only one of custom certs or LE can be set,