First draft implementation for scheme handler registry

.gitignore

@@ -54,3 +54,6 @@ test.json
 .idea/
 *.iml
 .vscode/
+
+# local test deployment-config
+deployment-config.json

CHANGES.md

@@ -1,6 +1,9 @@
 # Release-Changelog
 
 ## TBD (TBD)
+### Features
+* Add option to register `SchemeHandlers` to deployment-config. See [deployment-config.md](docs/deployment-config.md).
+
 ### Changes
 * Raise minimum golang requirement to 1.17
 

cmd/bundown/main.go

@@ -6,7 +6,6 @@ import (
 	"flag"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"strings"
@@ -145,7 +144,7 @@ func isFolder(filePath string) bool {
 }
 
 func mustReaderForFile(filePath string) io.Reader {
-	data, err := ioutil.ReadFile(filePath)
+	data, err := os.ReadFile(filePath)
 	if err != nil {
 		fatalf("Could not read file \"%s\": %v", filePath, err)
 	}

cmd/echo_field/main.go

@@ -5,7 +5,6 @@ import (
 	"flag"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"os"
 
 	"github.com/setlog/trivrost/pkg/launcher/config"
@@ -38,7 +37,7 @@ func parseFlags() {
 }
 
 func mustReaderForFile(filePath string) io.Reader {
-	data, err := ioutil.ReadFile(filePath)
+	data, err := os.ReadFile(filePath)
 	if err != nil {
 		fatalf("Could not read file \"%s\": %v", filePath, err)
 	}

cmd/installdown/main.go

@@ -241,7 +241,7 @@ func configure() *wxsConfig {
 }
 
 func mustReaderForFile(filePath string) io.Reader {
-	data, err := ioutil.ReadFile(filePath)
+	data, err := os.ReadFile(filePath)
 	if err != nil {
 		fatalf("Could not read file \"%s\": %v", filePath, err)
 	}

cmd/launcher/launcher/install.go

@@ -1,16 +1,18 @@
 package launcher
 
 import (
+	"github.com/setlog/systemuri"
+	"github.com/setlog/trivrost/cmd/launcher/flags"
+	"github.com/setlog/trivrost/cmd/launcher/resources"
+	"github.com/setlog/trivrost/pkg/launcher/config"
 	"os/exec"
 	"path/filepath"
 	"runtime"
+	"sort"
 	"strings"
 	"sync"
 	"time"
 
-	"github.com/setlog/trivrost/cmd/launcher/flags"
-	"github.com/setlog/trivrost/cmd/launcher/resources"
-
 	"github.com/setlog/trivrost/cmd/launcher/places"
 
 	log "github.com/sirupsen/logrus"
@@ -43,12 +45,12 @@ func IsInstanceInstalled() bool {
 	return isInstalled
 }
 
-// IsInstanceInstalledInSystemMode returns true iff we are in system mode.
+// IsInstanceInstalledInSystemMode returns true if we are in system mode.
 func IsInstanceInstalledInSystemMode() bool {
 	return system.FolderExists(places.GetSystemWideBundleFolderPath())
 }
 
-// IsInstanceInstalledForCurrentUser returns true iff the launcher's desired path under user files is occupied by the program running this code.
+// IsInstanceInstalledForCurrentUser returns true if the launcher's desired path under user files is occupied by the program running this code.
 func IsInstanceInstalledForCurrentUser() bool {
 	programPath := system.GetProgramPath()
 	targetProgramPath := getTargetProgramPath()
@@ -111,6 +113,8 @@ func Install(launcherFlags *flags.LauncherFlags) {
 
 	InstallShortcuts(targetProgramPath, launcherFlags)
 
+	// Registering the scheme handlers had to happen in run.go, since we do not have the deployment config here, yet.
+
 	MustRestartWithInstalledBinary(launcherFlags)
 }
 
@@ -124,6 +128,82 @@ func InstallShortcuts(targetProgramPath string, launcherFlags *flags.LauncherFla
 	waitGroup.Wait()
 }
 
+// RegisterSchemeHandlers registers the schemes defined in the deployment config
+func RegisterSchemeHandlers(launcherFlags *flags.LauncherFlags, schemeHandlers []config.SchemeHandler) {
+	transmittingFlags := launcherFlags.GetTransmittingFlags()
+	for _, schemeHandler := range schemeHandlers {
+		// TODO: Create flag "-lockagnostic" (or such) to allow to eliminate all self-restarting behavior (when used in combination with "-skipselfupdate") to reduce UI flickering?
+		// TODO: Create and then always add flag "-skipschemehandlerregistry" (or such) here to prevent -extra-env from being added?
+		// TODO: systemuri does not presently implement %%-escapes according to deployment-config.md.
+		binaryPath := system.GetBinaryPath()
+		// We want to pass a few flags from the current execution (transmitting flags) as well, but only if they are not set in the passed arguments.
+		finalArguments := []string{}
+		finalArguments = removeFromList(transmittingFlags, extractArguments(schemeHandler.Arguments))
+		finalArguments = filterWhitelistArguments(finalArguments)
+
+		transmittingFlagsFiltered := removeFromList(transmittingFlags, finalArguments)
+		transmittingFlagsFiltered = []string{} // TODO: We actually want to create a whitelist here of flags that are okay to retain
+
+		arguments := strings.Join(transmittingFlagsFiltered, " ") + schemeHandler.Arguments
+		err := systemuri.RegisterURLHandler(resources.LauncherConfig.BrandingName, schemeHandler.Scheme, binaryPath, arguments)
+		if err != nil {
+			log.Warnf("Registering the scheme \"%s\" failed: %v", schemeHandler.Scheme, err)
+		}
+	}
+}
+
+// TODO: Make case insensitive
+func filterWhitelistArguments(arguments []string) []string {
+	// slice of entries to allow in the arguments list
+	whitelist := []string{
+		"debug",
+		"skipselfupdate",
+		"roaming",
+		"deployment-config",
+		"extra-env",
+	}
+
+	var filteredArguments []string
+
+	sort.Strings(whitelist)
+	for _, argument := range arguments {
+		if found := sort.SearchStrings(whitelist, argument); found < len(whitelist) && whitelist[found] == argument {
+			continue
+		}
+		filteredArguments = append(filteredArguments, argument)
+	}
+
+	return filteredArguments
+}
+
+// TODO: Make case insensitive
+func removeFromList(sourceList []string, itemsToRemove []string) []string {
+	argSet := make(map[string]bool)
+	for _, item := range itemsToRemove {
+		argSet[item] = true
+	}
+
+	var filteredSourceList []string
+	for _, item := range sourceList {
+		if _, ok := argSet[item]; !ok {
+			filteredSourceList = append(filteredSourceList, item)
+		}
+	}
+	return filteredSourceList
+}
+
+func extractArguments(input string) []string {
+	words := strings.Fields(input)
+	var args []string
+	for _, w := range words {
+		if strings.HasPrefix(w, "-") || strings.HasPrefix(w, "--") {
+			arg := strings.SplitN(w, "=", 2)[0]
+			args = append(args, arg)
+		}
+	}
+	return args
+}
+
 func MustRestartWithInstalledBinary(launcherFlags *flags.LauncherFlags) {
 	locking.RestartWithBinary(true, getTargetBinaryPath(), launcherFlags)
 }

cmd/launcher/launcher/run.go

@@ -2,14 +2,12 @@ package launcher
 
 import (
 	"context"
-
-	"github.com/setlog/trivrost/pkg/launcher/config"
-
 	"github.com/setlog/trivrost/cmd/launcher/flags"
 	"github.com/setlog/trivrost/cmd/launcher/gui"
 	"github.com/setlog/trivrost/cmd/launcher/locking"
 	"github.com/setlog/trivrost/cmd/launcher/places"
 	"github.com/setlog/trivrost/cmd/launcher/resources"
+	"github.com/setlog/trivrost/pkg/launcher/config"
 
 	"github.com/setlog/trivrost/pkg/fetching"
 	"github.com/setlog/trivrost/pkg/logging"
@@ -24,7 +22,7 @@ func Run(ctx context.Context, launcherFlags *flags.LauncherFlags) {
 	updater := createUpdater(ctx, wireHandler(gui.NewGuiDownloadProgressHandler(fetching.MaxConcurrentDownloads)))
 
 	gui.SetStage(gui.StageGetDeploymentConfig, 0)
-	updater.Prepare(resources.LauncherConfig.DeploymentConfigURL)
+	updater.ObtainDeploymentConfig(resources.LauncherConfig.DeploymentConfigURL)
 
 	if !IsInstanceInstalledInSystemMode() && !launcherFlags.SkipSelfUpdate {
 		updateLauncherToLatestVersion(updater, launcherFlags)
@@ -33,6 +31,8 @@ func Run(ctx context.Context, launcherFlags *flags.LauncherFlags) {
 
 	gui.SetStage(gui.StageLaunchApplication, 0)
 	handleUpdateOmissions(ctx, updater)
+	// Registering the schema handlers here instead of install.go, since we have the updater (deployment config) here
+	RegisterSchemeHandlers(launcherFlags, updater.GetDeploymentConfig().SchemeHandlers)
 	launch(ctx, updater.GetDeploymentConfig().Execution, launcherFlags)
 }
 

cmd/launcher/launcher/uninstall.go

@@ -7,6 +7,7 @@ import (
 	"regexp"
 	"runtime"
 
+	"github.com/setlog/systemuri"
 	"github.com/setlog/trivrost/cmd/launcher/locking"
 
 	"github.com/setlog/trivrost/cmd/launcher/flags"
@@ -38,11 +39,21 @@ func uninstall(launcherFlags *flags.LauncherFlags) {
 	gui.ShowWaitDialog("Uninstalling "+brandingName, "Please wait as "+brandingName+" is uninstalling.")
 	deletePlainFiles()
 	deleteBundles()
+	unregisterSchemeHandlers()
 	defer prepareProgramDeletionWithFinalizerFunc()()
 	gui.HideWaitDialog()
 	gui.BlockingDialog("Uninstallation complete", brandingName+" has been uninstalled.", []string{"Close"}, 0, launcherFlags.DismissGuiPrompts)
 }
 
+// unregisterSchemeHandlers removes all handlers that are associated with this binary
+func unregisterSchemeHandlers() {
+	binaryPath := system.GetBinaryPath()
+	err := systemuri.UnregisterURLHandlerByPath(binaryPath)
+	if err != nil {
+		log.Warnf("Unregistering the schemes for binary \"%s\" failed: %v", binaryPath, err)
+	}
+}
+
 func deletePlainFiles() {
 	deleteDesktopShortcuts()
 	if runtime.GOOS != system.OsMac {

cmd/launcher/locking/signature_io.go

@@ -3,15 +3,14 @@ package locking
 import (
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
 	"os"
 
 	"github.com/setlog/trivrost/pkg/system"
 	log "github.com/sirupsen/logrus"
 )
 
 func readProcessSignatureListFile(filePath string) (procSigs []system.ProcessSignature) {
-	bytes, err := ioutil.ReadFile(filePath)
+	bytes, err := os.ReadFile(filePath)
 	if err != nil {
 		if os.IsNotExist(err) {
 			return nil
@@ -36,7 +35,7 @@ func mustWriteProcessSignatureListFile(filePath string, procSigs []system.Proces
 	if err != nil {
 		panic(fmt.Sprintf("Could not marshal process signature slice of length %d: %v", len(procSigs), err))
 	}
-	err = ioutil.WriteFile(filePath, bytes, 0666)
+	err = os.WriteFile(filePath, bytes, 0666)
 	if err != nil {
 		panic(fmt.Sprintf("Could not write process signature list file \"%s\": %v", filePath, err))
 	}

cmd/metawriter/main.go

@@ -5,7 +5,6 @@ import (
 	"flag"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"os"
 	"strconv"
 	"strings"
@@ -56,7 +55,7 @@ func replacePlaceholders(text string) string {
 
 func mustReadFile(filePath string) string {
 	fmt.Printf("Metawriter: Reading \"%s\".\n", filePath)
-	data, err := ioutil.ReadFile(filePath)
+	data, err := os.ReadFile(filePath)
 	if err != nil {
 		fatalf("Could not read \"%s\": %v", filePath, err)
 	}
@@ -65,7 +64,7 @@ func mustReadFile(filePath string) string {
 
 func mustWriteFile(filePath string, data []byte) {
 	fmt.Printf("Metawriter: Writing \"%s\".\n", filePath)
-	err := ioutil.WriteFile(filePath, data, 0600)
+	err := os.WriteFile(filePath, data, 0600)
 	if err != nil {
 		fatalf("Could not open file \"%s\" for writing: %v", filePath, err)
 	}
@@ -108,7 +107,7 @@ func validateVariables() {
 }
 
 func mustReaderForFile(filePath string) io.Reader {
-	data, err := ioutil.ReadFile(filePath)
+	data, err := os.ReadFile(filePath)
 	if err != nil {
 		fatalf("Could not read file \"%s\": %v", filePath, err)
 	}

cmd/signer/main.go

@@ -10,7 +10,6 @@ import (
 	"encoding/pem"
 	"flag"
 	"fmt"
-	"io/ioutil"
 	"os"
 )
 
@@ -35,7 +34,8 @@ func createSignatures() {
 		if err != nil {
 			fatalf("Creating of a signature for the file %s failed: %v", targetFiles[i], err)
 		}
-		if err = ioutil.WriteFile(targetFiles[i]+".signature", []byte(signature), 0644); err != nil {
+
+		if err = os.WriteFile(targetFiles[i]+".signature", []byte(signature), 0644); err != nil {
 			fatalf("Could not write a signature into the file %s.signature: %v", targetFiles[i], err)
 		}
 	}
@@ -55,7 +55,7 @@ func createFileSignature(key *rsa.PrivateKey, fileContent []byte) (string, error
 }
 
 func readFile(fileName string) []byte {
-	content, err := ioutil.ReadFile(fileName)
+	content, err := os.ReadFile(fileName)
 	if err != nil {
 		fatalf("Could not read a file %s: %v", fileName, err)
 	}

cmd/validator/http.go

@@ -2,19 +2,20 @@ package main
 
 import (
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"net/url"
+	"os"
 	"time"
 )
 
 func getFile(fileUrlString string) ([]byte, error) {
 	fileUrl, err := url.Parse(fileUrlString)
 	if err == nil && fileUrl.Scheme == "file" {
 		fileUrl.Scheme = ""
-		return ioutil.ReadFile(fileUrl.String())
+		return os.ReadFile(fileUrl.String())
 	} else if err != nil || fileUrl.Scheme == "" {
-		return ioutil.ReadFile(fileUrlString)
+		return os.ReadFile(fileUrlString)
 	}
 
 	client := &http.Client{}
@@ -27,7 +28,7 @@ func getFile(fileUrlString string) ([]byte, error) {
 	if resp.StatusCode != http.StatusOK {
 		return nil, fmt.Errorf("received bad status code %s", resp.Status)
 	}
-	return ioutil.ReadAll(resp.Body)
+	return io.ReadAll(resp.Body)
 }
 
 func getHttpHeadResult(url string) (responseCode int, err error) {

docs/deployment-config.md

@@ -5,6 +5,9 @@ The deployment-config is a JSON-file which is supposed to be hosted on a webserv
 ## Fields
 
 * **`Timestamp`** (string): A timestamp in the form `YYYY-MM-DD HH:mm:SS` which indicates when the deployment-config was last changed. This field protects trivrost against attacks. A utility script `script/insert_timestamp` is provided, which replaces a placeholder with a current timestamp. It can be called like this: `insert_timestamp "<TIMESTAMP>" …/deployment-config.json`. See [security.md](security.md) for more information.
+* **`SchemeHandlers`** (array): An array of objects which define scheme handlers to be registered with the operating system to run this trivrost app with a specified command line. The idea is to use it in combination with the `--extra-env` commandline option to pass info to the launched application. See also the [exhaustive example](../examples/deployment-config.json.complex.example) of the deployment-config.
+  * **`Scheme`** (string): The scheme for which to register the handler, such as `mailto`. We recommend to use some sort of reverse-DNS scheme, e.g. `com.example.productname.customername`.
+  * **`Arguments`** (string): The arguments to pass. Any occurrences of the special string `%s` will be replaced with the operating system-specific template which receives the resource part of the URL (i.e. path, query and fragment). Any occurrences of `%%` will be replaced with `%` to allow for a literal string `%s` to be written (we do not recommend doing so).
 * **`LauncherUpdate`** (array): An array of objects which define bundle configurations for how trivrost updates itself. When trivrost runs, this list must boil down to either one single configuration, or no configurations, through filtering by `TargetPlatforms`.
   * **`BundleInfoURL`**, **`BaseURL`**, **`TargetPlatforms`**: See [Common fields](#Common-fields) below.
 * **`Bundles`** (array): An array of objects which define the bundles which trivrost should download and keep up to date.

docs/glossary.md

@@ -20,3 +20,6 @@ The deployment config tells trivrost where to check for updates to itself and it
 
 ## trivrost deployment artifact
 We occasionally need to differ between just trivrost's executable binary and its entire deployment artifact as a whole. On Windows and Linux these two concepts are the same thing. On MacOS however, the deployment artifact of trivrost actually is a `.app`-folder, which contains the binary at `Contents/MacOS/launcher`.
+
+## Transmitting flags
+Whenever trivrost restarts itself as part of its exclusive lock and self-update mechanisms, it passes most of the command line arguments it was run with (such as `-skipselfupdate`) to the new instance as well. We refer to arguments affected by this as "transmitting flags".