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Overview

The security package provides comprehensive safety mechanisms for the Camera Workflow application, including disk space verification, file integrity checks, processing markers, and automatic recovery from interrupted operations.

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Types

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SecurityChecker

Main security checker that performs validation and safety operations. 
type SecurityChecker struct {
    minOutputSizeRatio     float64
    minOutputSizeRatioAVIF float64
    minOutputSizeRatioWebP float64
}
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minOutputSizeRatio
float64
Minimum size ratio for general output validation (default: 0.005)
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minOutputSizeRatioAVIF
float64
Minimum size ratio for AVIF files (default: 0.001)
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minOutputSizeRatioWebP
float64
Minimum size ratio for WebP files (default: 0.003)

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Functions

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NewSecurityChecker

Creates a new SecurityChecker instance. 
func NewSecurityChecker(
    minOutputSizeRatio,
    minOutputSizeRatioAVIF,
    minOutputSizeRatioWebP float64,
) *SecurityChecker
​
minOutputSizeRatio
float64
required
Minimum acceptable output size ratio (output_size / input_size)
​
minOutputSizeRatioAVIF
float64
required
Format-specific ratio for AVIF files
​
minOutputSizeRatioWebP
float64
required
Format-specific ratio for WebP files

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Example

import "github.com/Azilone/Camera-Workflow/internal/security"

checker := security.NewSecurityChecker(0.005, 0.001, 0.003)

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Methods

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CheckDiskSpace

Verifies that sufficient disk space is available for conversion. 
func (s *SecurityChecker) CheckDiskSpace(sourceDir, destDir string) error
​
sourceDir
string
required
Path to source directory
​
destDir
string
required
Path to destination directory
​
error
error
Returns an error if insufficient disk space is available

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Example

if err := checker.CheckDiskSpace("/source", "/dest"); err != nil {
    log.Fatalf("Insufficient disk space: %v", err)
}

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Space Calculation

  • Estimates needed space as 50% of source directory size
  • Compares against available space in destination
  • Platform-specific implementations for accurate free space detection

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VerifyOutputFile

Performs comprehensive validation of a converted output file. 
func (s *SecurityChecker) VerifyOutputFile(
    inputPath,
    outputPath,
    fileType,
    outputFormat string,
) error
​
inputPath
string
required
Path to original input file
​
outputPath
string
required
Path to converted output file
​
fileType
string
required
Type of file (“photo” or “video”)
​
outputFormat
string
required
Output format (“avif”, “webp”, “mp4”, etc.)
​
error
error
Returns an error if validation fails (file is corrupted or too small)

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Validation Steps

  1. Existence Check: Verify output file exists
  2. Size Check: Ensure file is not empty
  3. Ratio Check: Validate minimum size ratio (format-specific)
  4. Integrity Check: Verify file can be opened by appropriate tool
    • Photos: Uses ImageMagick identify
    • Videos: Uses FFmpeg ffprobe

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Example

err := checker.VerifyOutputFile(
    "/source/photo.jpg",
    "/dest/photo.avif",
    "photo",
    "avif",
)
if err != nil {
    log.Printf("Verification failed: %v", err)
}

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SafeDelete

Safely deletes an original file after triple verification. 
func (s *SecurityChecker) SafeDelete(filePath, outputPath string) error
​
filePath
string
required
Path to original file to delete
​
outputPath
string
required
Path to converted output file (must exist and be valid)
​
error
error
Returns an error if deletion is unsafe or fails

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Safety Checks

  1. Output file exists
  2. Output file is not empty
  3. Output file size > 1000 bytes (minimum threshold)

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IsFileCorrupted

Checks if an existing file is corrupted or incomplete. 
func (s *SecurityChecker) IsFileCorrupted(filePath, fileType string) bool
​
filePath
string
required
Path to file to check
​
fileType
string
required
Type of file (“photo” or “video”)
​
corrupted
bool
Returns true if file is corrupted, missing, or invalid

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Example

if checker.IsFileCorrupted("/dest/photo.avif", "photo") {
    log.Println("File is corrupted, will re-convert")
    os.Remove("/dest/photo.avif")
}

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CreateProcessingMarker

Creates a marker file to track active conversions. 
func (s *SecurityChecker) CreateProcessingMarker(filePath string) error
​
filePath
string
required
Path to file being converted
​
error
error
Returns an error if marker creation fails

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Marker Format

Creates a .processing file containing: 
PID:12345
Started:2026-03-03T10:30:00Z
File:/path/to/file.jpg

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RemoveProcessingMarker

Removes the processing marker after conversion completes. 
func (s *SecurityChecker) RemoveProcessingMarker(filePath string) error
​
filePath
string
required
Path to file (marker is filePath + “.processing”)

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FindAbandonedMarkers

Finds processing markers from previous runs where the process has died. 
func (s *SecurityChecker) FindAbandonedMarkers(dir string) ([]string, error)
​
dir
string
required
Directory to search for abandoned markers
​
markers
[]string
List of abandoned marker file paths
​
error
error
Returns an error if directory traversal fails

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Detection Logic

  1. Finds all .processing files
  2. Reads PID from marker file
  3. Checks if process with that PID still exists
  4. Returns markers where process is dead

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CleanupAbandonedFiles

Removes temporary and abandoned files from interrupted conversions. 
func (s *SecurityChecker) CleanupAbandonedFiles(dir string) error
​
dir
string
required
Directory to clean up
​
error
error
Returns an error if cleanup fails

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Cleanup Targets

  • .tmp files (temporary conversion outputs)
  • .processing markers from dead processes

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VerifyFileIntegrity

Performs comprehensive integrity check on a file. 
func (s *SecurityChecker) VerifyFileIntegrity(
    filePath,
    fileType string,
) error
​
filePath
string
required
Path to file to verify
​
fileType
string
required
Type of file (“photo” or “video”)
​
error
error
Returns an error if file is corrupted or inaccessible

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Verification Steps

  1. File exists
  2. File is not empty
  3. File can be opened
  4. First 1KB can be read
  5. Type-specific validation (ImageMagick or FFprobe)

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Platform-Specific Functions

The package includes platform-specific implementations for:

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Disk Space Detection

  • Unix/Linux: diskspace_unix.go - Uses syscall.Statfs
  • Windows: diskspace_windows.go - Uses Windows API

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Process Checking

  • Unix/Linux: process_check_unix.go - Checks /proc/{pid}
  • Windows: process_check_windows.go - Uses Windows process API

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Safety Guarantees

The security package ensures:
  1. No data loss: Triple verification before deletion
  2. Atomic operations: Files converted to .tmp then renamed
  3. Crash recovery: Processing markers enable automatic recovery
  4. Integrity validation: All outputs verified with external tools
  5. Space safety: Pre-flight disk space checks
  • Converter - Uses SecurityChecker for validation
  • Config - Provides security thresholds
  • Utils - Platform-agnostic utility functions

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