✨ Add support for custom environment vars (#183)

This commit adds support for custom environment variables, which can be
set in PHP Monitor's custom configuration file.

Let's say you wish to customize the `COMPOSER_HOME` env variable, like
in #183. You can fix this like so:

```json
{
    "scan_apps": [],
    "services": [],
    "presets": []
    "export": {
        "COMPOSER_HOME": "/absolute/path/to/composer/folder"
    }
}
```

Please note that while it is possible to set the `PATH` this way, you
WILL MOST CERTAINLY break PHP Monitor in the process. Setting other
environment variables should generally not pose an issue, unless said
environment variable affects the output of the shell that PHP Monitor
uses internally.

phpmon/Common/Core/Shell.swift

@@ -32,6 +32,9 @@ public class Shell {
      */
     public var shell: String = "/bin/sh"
 
+    /** Additional exports that are sent if `requiresPath` is set to true. */
+    public var exports: String = ""
+
     /**
      Singleton to access a user shell (with --login)
      */
@@ -114,13 +117,23 @@ public class Shell {
      Creates a new process with the correct PATH and shell.
      */
     public func createTask(for command: String, requiresPath: Bool) -> Process {
-        let tailoredCommand = requiresPath
-        ? "export PATH=\(Paths.binPath):$PATH && \(command)"
-        : command
+        var completeCommand = ""
+
+        if requiresPath {
+            // Basic export (PATH)
+            completeCommand += "export PATH=\(Paths.binPath):$PATH && "
+
+            // Put additional exports in between
+            if !self.exports.isEmpty {
+                completeCommand += "\(self.exports) && "
+            }
+        }
+
+        completeCommand += command
 
         let task = Process()
         task.launchPath = self.shell
-        task.arguments = ["--noprofile", "-norc", "--login", "-c", tailoredCommand]
+        task.arguments = ["--noprofile", "-norc", "--login", "-c", completeCommand]
 
         return task
     }

phpmon/Domain/Preferences/CustomPrefs.swift

@@ -12,6 +12,7 @@ struct CustomPrefs: Decodable {
     let scanApps: [String]
     let presets: [Preset]?
     let services: [String]?
+    let environmentVariables: [String: String]?
 
     public func hasPresets() -> Bool {
         return self.presets != nil && !self.presets!.isEmpty
@@ -21,9 +22,20 @@ struct CustomPrefs: Decodable {
         return self.services != nil && !self.services!.isEmpty
     }
 
+    public func hasEnvironmentVariables() -> Bool {
+        return self.environmentVariables != nil && !self.environmentVariables!.keys.isEmpty
+    }
+
+    public func getEnvironmentVariables() -> String {
+        return self.environmentVariables!.map { (key, value) in
+            return "export \(key)=\(value)"
+        }.joined(separator: "&&")
+    }
+
     private enum CodingKeys: String, CodingKey {
         case scanApps = "scan_apps"
         case presets = "presets"
         case services = "services"
+        case environmentVariables = "export"
     }
 }

phpmon/Domain/Preferences/Preferences.swift

@@ -65,7 +65,7 @@ class Preferences {
     public init() {
         Preferences.handleFirstTimeLaunch()
         cachedPreferences = Self.cache()
-        customPreferences = CustomPrefs(scanApps: [], presets: [], services: [])
+        customPreferences = CustomPrefs(scanApps: [], presets: [], services: [], environmentVariables: [:])
         loadCustomPreferences()
     }
 
@@ -252,6 +252,11 @@ class Preferences {
             if customPreferences.hasServices() {
                 Log.info("There are custom services: \(customPreferences.services!)")
             }
+
+            if customPreferences.hasEnvironmentVariables() {
+                Log.info("Configuring the additional exports...")
+                Shell.user.exports = customPreferences.getEnvironmentVariables()
+            }
         } catch {
             Log.warn("The ~/.config/phpmon/config.json file seems to be missing or malformed.")
         }