Struct MimeValidator 

pub struct MimeValidator { /* private fields */ }

MIME type validator using magic number detection

This validator uses file signatures (magic numbers) to determine the actual file type, providing security against forged Content-Type headers.

Implementations

impl MimeValidator

pub const fn new() -> Self

Creates a new MIME validator

Examples

use acton_htmx::storage::validation::MimeValidator;

let validator = MimeValidator::new();

pub const fn permissive() -> Self

Creates a validator in permissive mode

In permissive mode, if the magic number cannot be detected, the validator falls back to checking the Content-Type header. This is useful for file types without clear magic numbers.

Warning: Permissive mode is less secure. Use only when necessary.

Examples

use acton_htmx::storage::validation::MimeValidator;

let validator = MimeValidator::permissive();

pub fn detect_mime(&self, file: &UploadedFile) -> Option<&'static str>

Detects the actual MIME type from file content

Uses magic number detection to determine the file type. Returns None if the file type cannot be determined.

Examples

use acton_htmx::storage::{UploadedFile, validation::MimeValidator};

let file = UploadedFile::new(
    "test.jpg",
    "application/octet-stream",
    vec![0xFF, 0xD8, 0xFF], // JPEG magic bytes
);

let validator = MimeValidator::new();
let detected = validator.detect_mime(&file);
assert_eq!(detected, Some("image/jpeg"));

pub fn validate_against_magic( &self, file: &UploadedFile, allowed_types: &[&str], ) -> StorageResult<()>

Validates file against allowed MIME types using magic number detection

This is the most secure validation method as it checks the actual file content rather than trusting the Content-Type header.

Errors

Returns StorageError::InvalidMimeType if:

• The detected type is not in allowed_types
• In strict mode: The file type cannot be detected

Examples

use acton_htmx::storage::{UploadedFile, validation::MimeValidator};

let file = UploadedFile::new(
    "photo.png",
    "image/png",
    vec![0x89, 0x50, 0x4E, 0x47], // PNG magic bytes
);

let validator = MimeValidator::new();
validator.validate_against_magic(&file, &["image/png", "image/jpeg"])?;

pub fn validate_header_matches_content( &self, file: &UploadedFile, ) -> StorageResult<()>

Validates that the Content-Type header matches the detected type

This ensures that the client-provided Content-Type header is accurate. Useful for detecting mismatches that might indicate malicious uploads.

Errors

Returns StorageError::InvalidMimeType if the header doesn’t match detected type

Examples

use acton_htmx::storage::{UploadedFile, validation::MimeValidator};

// Honest upload - header matches content
let honest = UploadedFile::new(
    "photo.jpg",
    "image/jpeg",
    vec![0xFF, 0xD8, 0xFF], // JPEG magic bytes
);

let validator = MimeValidator::new();
validator.validate_header_matches_content(&honest)?;

// Dishonest upload - header lies about content
let dishonest = UploadedFile::new(
    "malware.jpg", // Claims to be JPEG
    "image/jpeg",
    b"#!/bin/sh\nrm -rf /".to_vec(), // But it's a shell script!
);

assert!(validator.validate_header_matches_content(&dishonest).is_err());

pub fn is_image(&self, file: &UploadedFile) -> bool

Checks if the file is an image

Examples

use acton_htmx::storage::{UploadedFile, validation::MimeValidator};

let image = UploadedFile::new(
    "photo.png",
    "image/png",
    vec![0x89, 0x50, 0x4E, 0x47], // PNG magic bytes
);

let validator = MimeValidator::new();
assert!(validator.is_image(&image));

let text = UploadedFile::new(
    "doc.txt",
    "text/plain",
    b"Hello, world!".to_vec(),
);
assert!(!validator.is_image(&text));

pub fn is_video(&self, file: &UploadedFile) -> bool

Checks if the file is a video

Examples

use acton_htmx::storage::{UploadedFile, validation::MimeValidator};

let video = UploadedFile::new(
    "clip.mp4",
    "video/mp4",
    vec![0x00, 0x00, 0x00, 0x18, 0x66, 0x74, 0x79, 0x70], // MP4 magic
);

let validator = MimeValidator::new();
assert!(validator.is_video(&video));

pub fn is_document(&self, file: &UploadedFile) -> bool

Checks if the file is a document (PDF, Office, etc.)

Examples

use acton_htmx::storage::{UploadedFile, validation::MimeValidator};

let pdf = UploadedFile::new(
    "doc.pdf",
    "application/pdf",
    vec![0x25, 0x50, 0x44, 0x46], // PDF magic bytes
);

let validator = MimeValidator::new();
assert!(validator.is_document(&pdf));

Trait Implementations

impl Clone for MimeValidator

fn clone(&self) -> MimeValidator

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for MimeValidator

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for MimeValidator

fn default() -> MimeValidator

Returns the “default value” for a type.