feat: add support for activating application by process id

closes: #63

README.md

@@ -36,10 +36,12 @@ Input can also be piped to `stdin`:
 cat example.txt | sendkeys --application-name "Notes"
 ```
 
-_Activates the Notes application and sends keystrokes piped from `stdout` of the preceeding command._
+_Activates the Notes application and sends keystrokes piped from `stdout` of the preceding command._
 
 Note that a list of applications that can be used in `--application-name` can be found using the
-[`apps` sub command](#list-of-applications-names)
+[`apps` sub command](#list-of-applications-names).
+
+Applications can also be activated using the running process id (`--pid` or `-p` option).
 
 ## Installation
 
@@ -302,7 +304,7 @@ sendkeys apps
 
 Sample output:
 
-```
+```text
 Code             id:com.microsoft.VSCode
 Finder           id:com.apple.finder
 Google Chrome    id:com.google.Chrome

Sources/SendKeysLib/AppActivator.swift

@@ -2,58 +2,79 @@ import Cocoa
 
 class AppActivator: NSObject {
     private var application: NSRunningApplication!
-    private let filterName: String
+    private let appName: String?
+    private let processId: Int?
 
-    init(appName: String) {
-        filterName = appName.lowercased()
+    init(appName: String?, processId: Int?) {
+        self.appName = appName?.lowercased()
+        self.processId = processId
     }
 
     func activate() throws {
         let apps = NSWorkspace.shared.runningApplications.filter({ a in
             return a.activationPolicy == .regular
         })
 
-        // exact match (case insensitive)
-        var app = apps.filter({ a in
-            return a.localizedName?.lowercased() == self.filterName
-                || a.bundleIdentifier?.lowercased() == self.filterName
-        }).first
+        var app: NSRunningApplication?
 
-        let expression = try! NSRegularExpression(
-            pattern: "\\b\(NSRegularExpression.escapedPattern(for: self.filterName))\\b", options: .caseInsensitive)
-
-        // partial name match
-        if app == nil {
+        if processId != nil {
             app =
                 apps.filter({ a in
-                    let nameMatch = expression.firstMatch(
-                        in: a.localizedName ?? "", options: [], range: NSMakeRange(0, a.localizedName?.utf16.count ?? 0)
-                    )
-                    return nameMatch != nil
+                    return a.processIdentifier == pid_t(processId!)
                 }).first
-        }
 
-        // patial bundle id match
-        if app == nil {
+            if app == nil {
+                throw RuntimeError(
+                    "Application with process id \(processId!) could not be found."
+                )
+            }
+        } else if appName != nil {
+            // exact match (case insensitive)
             app =
                 apps.filter({ a in
-                    let bundleMatch = expression.firstMatch(
-                        in: a.bundleIdentifier ?? "", options: [],
-                        range: NSMakeRange(0, a.bundleIdentifier?.utf16.count ?? 0))
-                    return bundleMatch != nil
+                    return a.localizedName?.lowercased() == appName
+                        || a.bundleIdentifier?.lowercased() == appName
                 }).first
-        }
 
-        if app == nil {
-            throw RuntimeError(
-                "Application \(self.filterName) could not be activated. Run `sendkeys apps` to see a list of applications that can be activated."
-            )
+            let expression = try! NSRegularExpression(
+                pattern: "\\b\(NSRegularExpression.escapedPattern(for: appName!))\\b", options: .caseInsensitive)
+
+            // partial name match
+            if app == nil {
+                app =
+                    apps.filter({ a in
+                        let nameMatch = expression.firstMatch(
+                            in: a.localizedName ?? "", options: [],
+                            range: NSMakeRange(0, a.localizedName?.utf16.count ?? 0)
+                        )
+                        return nameMatch != nil
+                    }).first
+            }
+
+            // patial bundle id match
+            if app == nil {
+                app =
+                    apps.filter({ a in
+                        let bundleMatch = expression.firstMatch(
+                            in: a.bundleIdentifier ?? "", options: [],
+                            range: NSMakeRange(0, a.bundleIdentifier?.utf16.count ?? 0))
+                        return bundleMatch != nil
+                    }).first
+            }
+
+            if app == nil {
+                throw RuntimeError(
+                    "Application \(appName!) cannot be activated. Run `sendkeys apps` to see a list of applications that can be activated."
+                )
+            }
         }
 
-        self.application = app
+        if app != nil {
+            self.application = app
 
-        self.unhideAppIfNeeded()
-        self.activateAppIfNeeded()
+            self.unhideAppIfNeeded()
+            self.activateAppIfNeeded()
+        }
     }
 
     private func unhideAppIfNeeded() {

Sources/SendKeysLib/Sender.swift

@@ -12,6 +12,11 @@ public struct Sender: ParsableCommand {
     @Option(name: .shortAndLong, help: "Name of a running application to send keys to.")
     var applicationName: String?
 
+    @Option(
+        name: NameSpecification([.short, .customLong("pid")]),
+        help: "Process id of a running application to send keys to.")
+    var processId: Int?
+
     @Option(name: .shortAndLong, help: "Default delay between keystrokes in seconds.")
     var delay: Double = 0.1
 
@@ -55,9 +60,7 @@ public struct Sender: ParsableCommand {
             commandString = characters
         }
 
-        if !(applicationName ?? "").isEmpty {
-            try AppActivator(appName: applicationName!).activate()
-        }
+        try AppActivator(appName: applicationName, processId: processId).activate()
 
         if initialDelay > 0 {
             Sleeper.sleep(seconds: initialDelay)