feat: Add SSH key authentication and custom port support (#97)

* feat: Add SSH key authentication and custom port support

- Add SSH key authentication support with three modes: password, key, or both
- Add custom SSH port support (defaults to 22)
- Create SSHKeyInput component with file upload and paste modes
- Update database schema with auth_type, ssh_key, ssh_key_passphrase, and ssh_port columns
- Update TypeScript interfaces to support new authentication fields
- Update SSH services to handle key authentication and custom ports
- Update ServerForm with authentication type selection and SSH port field
- Update API routes with validation for new fields
- Add proper cleanup for temporary SSH key files
- Support for encrypted SSH keys with passphrase protection
- Maintain backward compatibility with existing password-only servers

* fix: Resolve TypeScript build errors and improve type safety

- Replace || operators with ?? (nullish coalescing) for better type safety
- Add proper null checks for password fields in SSH services
- Fix JSDoc type annotations for better TypeScript inference
- Update error object types to use Record<keyof CreateServerData, string>
- Ensure all SSH authentication methods handle optional fields correctly

Author: michelroegl-brunner

src/app/_components/SSHKeyInput.tsx

@@ -0,0 +1,191 @@
+'use client';
+
+import { useState, useRef } from 'react';
+import { Button } from './ui/button';
+
+interface SSHKeyInputProps {
+  value: string;
+  onChange: (value: string) => void;
+  onError?: (error: string) => void;
+  disabled?: boolean;
+}
+
+export function SSHKeyInput({ value, onChange, onError, disabled = false }: SSHKeyInputProps) {
+  const [inputMode, setInputMode] = useState<'upload' | 'paste'>('upload');
+  const [isDragOver, setIsDragOver] = useState(false);
+  const fileInputRef = useRef<HTMLInputElement>(null);
+
+  const validateSSHKey = (keyContent: string): boolean => {
+    const trimmed = keyContent.trim();
+    return (
+      trimmed.includes('BEGIN') &&
+      trimmed.includes('PRIVATE KEY') &&
+      trimmed.includes('END') &&
+      trimmed.includes('PRIVATE KEY')
+    );
+  };
+
+  const handleFileUpload = (file: File) => {
+    if (!file) return;
+
+    const reader = new FileReader();
+    reader.onload = (e) => {
+      const content = e.target?.result as string;
+      if (validateSSHKey(content)) {
+        onChange(content);
+        onError?.('');
+      } else {
+        onError?.('Invalid SSH key format. Please ensure the file contains a valid private key.');
+      }
+    };
+    reader.onerror = () => {
+      onError?.('Failed to read the file. Please try again.');
+    };
+    reader.readAsText(file);
+  };
+
+  const handleFileSelect = (event: React.ChangeEvent<HTMLInputElement>) => {
+    const file = event.target.files?.[0];
+    if (file) {
+      handleFileUpload(file);
+    }
+  };
+
+  const handleDragOver = (event: React.DragEvent) => {
+    event.preventDefault();
+    setIsDragOver(true);
+  };
+
+  const handleDragLeave = (event: React.DragEvent) => {
+    event.preventDefault();
+    setIsDragOver(false);
+  };
+
+  const handleDrop = (event: React.DragEvent) => {
+    event.preventDefault();
+    setIsDragOver(false);
+    
+    const file = event.dataTransfer.files[0];
+    if (file) {
+      handleFileUpload(file);
+    }
+  };
+
+  const handlePasteChange = (event: React.ChangeEvent<HTMLTextAreaElement>) => {
+    const content = event.target.value;
+    onChange(content);
+    
+    if (content.trim() && !validateSSHKey(content)) {
+      onError?.('Invalid SSH key format. Please ensure the content is a valid private key.');
+    } else {
+      onError?.('');
+    }
+  };
+
+  const getKeyFingerprint = (keyContent: string): string => {
+    // This is a simplified fingerprint - in a real implementation,
+    // you might want to use a library to generate proper SSH key fingerprints
+    if (!keyContent.trim()) return '';
+    
+    const lines = keyContent.trim().split('\n');
+    const keyLine = lines.find(line => 
+      line.includes('BEGIN') && line.includes('PRIVATE KEY')
+    );
+    
+    if (keyLine) {
+      const keyType = keyLine.includes('RSA') ? 'RSA' : 
+                     keyLine.includes('ED25519') ? 'ED25519' : 
+                     keyLine.includes('ECDSA') ? 'ECDSA' : 'Unknown';
+      return `${keyType} key (${keyContent.length} characters)`;
+    }
+    
+    return 'Unknown key type';
+  };
+
+  return (
+    <div className="space-y-4">
+      {/* Mode Toggle */}
+      <div className="flex space-x-2">
+        <Button
+          type="button"
+          variant={inputMode === 'upload' ? 'default' : 'outline'}
+          size="sm"
+          onClick={() => setInputMode('upload')}
+          disabled={disabled}
+        >
+          Upload File
+        </Button>
+        <Button
+          type="button"
+          variant={inputMode === 'paste' ? 'default' : 'outline'}
+          size="sm"
+          onClick={() => setInputMode('paste')}
+          disabled={disabled}
+        >
+          Paste Key
+        </Button>
+      </div>
+
+      {/* File Upload Mode */}
+      {inputMode === 'upload' && (
+        <div
+          className={`border-2 border-dashed rounded-lg p-6 text-center transition-colors ${
+            isDragOver
+              ? 'border-primary bg-primary/5'
+              : 'border-border hover:border-primary/50'
+          } ${disabled ? 'opacity-50 cursor-not-allowed' : 'cursor-pointer'}`}
+          onDragOver={handleDragOver}
+          onDragLeave={handleDragLeave}
+          onDrop={handleDrop}
+          onClick={() => !disabled && fileInputRef.current?.click()}
+        >
+          <input
+            ref={fileInputRef}
+            type="file"
+            accept=".pem,.key,.id_rsa,.id_ed25519,.id_ecdsa"
+            onChange={handleFileSelect}
+            className="hidden"
+            disabled={disabled}
+          />
+          <div className="space-y-2">
+            <div className="text-lg">📁</div>
+            <p className="text-sm text-muted-foreground">
+              Drag and drop your SSH private key here, or click to browse
+            </p>
+            <p className="text-xs text-muted-foreground">
+              Supported formats: RSA, ED25519, ECDSA (.pem, .key, .id_rsa, etc.)
+            </p>
+          </div>
+        </div>
+      )}
+
+      {/* Paste Mode */}
+      {inputMode === 'paste' && (
+        <div className="space-y-2">
+          <label className="text-sm font-medium text-muted-foreground">
+            Paste your SSH private key:
+          </label>
+          <textarea
+            value={value}
+            onChange={handlePasteChange}
+            placeholder="-----BEGIN OPENSSH PRIVATE KEY-----&#10;b3BlbnNzaC1rZXktdjEAAAAABG5vbmUAAAAEbm9uZQAAAAAAAAABFwAAAAdzc2gtcn...&#10;-----END OPENSSH PRIVATE KEY-----"
+            className="w-full h-32 px-3 py-2 border rounded-md shadow-sm bg-card text-foreground placeholder-muted-foreground focus:outline-none focus:ring-2 focus:ring-ring focus:border-ring font-mono text-xs"
+            disabled={disabled}
+          />
+        </div>
+      )}
+
+      {/* Key Information */}
+      {value && (
+        <div className="p-3 bg-muted rounded-md">
+          <div className="text-sm">
+            <span className="font-medium">Key detected:</span> {getKeyFingerprint(value)}
+          </div>
+          <div className="text-xs text-muted-foreground mt-1">
+            ⚠️ Keep your private keys secure. This key will be stored in the database.
+          </div>
+        </div>
+      )}
+    </div>
+  );
+}