1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158

//! A collection of DICOM files for testing DICOM parsers.
//!
//! To avoid users having to download all the files they are downloaded as they
//! are needed and cached in the `/target` directory.
//!
//! ```no_run
//! use dicom_test_files;
//!
//! dicom_test_files::path("pydicom/liver.dcm").unwrap();
//! ```
#![deny(missing_docs)]

use sha2::{Digest, Sha256};
use std::{
    env, fs, io,
    path::{Path, PathBuf},
};

mod hashes;

use crate::hashes::FILE_HASHES;

/// Error type for test_dicom_files
#[derive(Debug)]
pub enum Error {
    /// Returned when the provided name does not exist in the hash list
    ///
    /// If you are sure it does exist you may need to update to a newer version dicom_test_files.
    NotFound,
    /// Returned when the hash of the downloaded file does not match the previously generated hash
    ///
    /// This may mean you need to update to a newer version of dicom_test_files.
    InvalidHash,
    /// Returned when the file cannot be downloaded. Contains the generated URL.
    Download(String),
    /// Wrapped errors from std::io
    Io(io::Error),
}

impl From<io::Error> for Error {
    fn from(err: io::Error) -> Error {
        Error::Io(err)
    }
}

/// Return the local path for a given DICOM file
///
/// This function will download and cache the file locally in `target/dicom_test_files`
/// if it has not already been downloaded.
pub fn path(name: &str) -> Result<PathBuf, Error> {
    let cached_path = get_data_path().join(name);
    if !cached_path.exists() {
        download(name, &cached_path)?;
    }
    Ok(cached_path)
}

/// Return a vector of local paths to all DICOM files
///
/// This function will download and cache the file locally in `target/dicom_test_files`
/// if it has not already been downloaded.
pub fn all() -> Result<Vec<PathBuf>, Error> {
    FILE_HASHES
        .iter()
        .map(|(name, _)| path(name))
        .collect::<Result<Vec<PathBuf>, Error>>()
}

pub(crate) fn get_data_path() -> PathBuf {
    let mut target_dir = PathBuf::from(
        env::current_exe()
            .expect("exe path")
            .parent()
            .expect("exe parent"),
    );
    while target_dir.file_name() != Some(std::ffi::OsStr::new("target")) {
        if !target_dir.pop() {
            panic!("Cannot find target directory");
        }
    }
    target_dir.join("dicom_test_files")
}

const GITHUB_BASE_URL: &str =
    "https://raw.githubusercontent.com/robyoung/dicom-test-files/master/data/";

fn download(name: &str, cached_path: &PathBuf) -> Result<(), Error> {
    check_hash_exists(name)?;

    fs::create_dir_all(cached_path.as_path().parent().unwrap())?;

    let url = GITHUB_BASE_URL.to_owned() + name;
    let resp = ureq::get(&url).call();
    if !resp.ok() {
        return Err(Error::Download(format!("Failed to download {}", url)));
    }
    let mut target = fs::File::create(cached_path.as_path())?;
    std::io::copy(&mut resp.into_reader(), &mut target)?;

    check_hash(cached_path.as_path(), name)?;

    Ok(())
}

fn check_hash_exists(name: &str) -> Result<(), Error> {
    for (hash_name, _) in FILE_HASHES.iter() {
        if *hash_name == name {
            return Ok(());
        }
    }
    Err(Error::NotFound)
}

fn check_hash(path: &Path, name: &str) -> Result<(), Error> {
    let mut file = fs::File::open(path)?;
    let mut hasher = Sha256::new();
    io::copy(&mut file, &mut hasher)?;
    let hash = hasher.result();

    for (hash_name, file_hash) in FILE_HASHES.iter() {
        if *hash_name == name {
            if format!("{:x}", hash) == *file_hash {
                return Ok(());
            } else {
                fs::remove_file(path)?;
                return Err(Error::InvalidHash);
            }
        }
    }

    unreachable!("file existance was checked before downloading");
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn load_a_single_path() {
        // ensure it does not exist
        let cached_path = get_data_path().join("pydicom/liver.dcm");
        if cached_path.exists() {
            fs::remove_file(cached_path).unwrap();
        }

        let path = path("pydicom/liver.dcm").unwrap();
        let path = path.as_path();

        assert_eq!(path.file_name().unwrap(), "liver.dcm");
        assert!(path.exists());
    }

    #[test]
    fn load_all_paths() {
        let all = all().unwrap();
        assert_eq!(all.len(), 126);
    }
}