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use crate::{Error, Additional, Extractor, http::Request};
use std::collections::HashMap;
use std::sync::Arc;
/// File contained in a multipart call
#[derive(Clone, Debug)]
pub struct File {
pub name: String,
pub filename: Option<String>,
pub content_type: Option<String>,
pub content: Vec<u8>
}
/// Multipart extractor
///
/// Meant to be used in functions to extract files from an http request
///
/// ```rust, no_run
/// # use cataclysm::http::{Response, Multipart};
/// async fn receive_file(multipart: Multipart) -> Response {
/// for file in multipart.files() {
/// if let Some(filename) = &file.filename {
/// log::info!("Found file {}, writing content", filename);
/// // Do something with the file...
/// }
/// }
/// Response::ok()
/// }
/// ```
pub struct Multipart {
raw_files: HashMap<String, File>
}
impl Multipart {
/// Retrieves a file from the multipart request by its name in the form
pub fn file_by_name<A: AsRef<str>>(&self, name: A) -> Option<&File> {
self.raw_files.get(name.as_ref())
}
/// Retrieves all files contained in the multipart as a vector
pub fn files(&self) -> Vec<&File> {
self.raw_files.iter().map(|(_n, v)| v).collect()
}
}
impl<T: Sync> Extractor<T> for Multipart {
fn extract(req: &Request, _additional: Arc<Additional<T>>) -> Result<Self, Error> {
if let Some(content_type) = req.headers.get("Content-Type") {
if let Some((multipart_tag, boundary_pair)) = content_type.trim().split_once(";") {
if multipart_tag == "multipart/form-data" {
if let Some((tag, boundary)) = boundary_pair.trim().split_once("=") {
if tag == "boundary" {
// We create a pair of iterators, subsequent
let mut main_iter = req.content.iter().zip(req.content.iter().skip(1)).enumerate();
let mut parts: Vec<&[u8]> = Vec::new();
let mut previous = 0;
loop {
if let Some((idx, (one, two))) = main_iter.next() {
if one == two && two == &b'-' {
// Let's see if this is a boundary
if idx + 2 + boundary.len() < req.content.len() {
// We extract it
if req.content.get(idx+2..idx+2+boundary.len()) == Some(boundary.as_bytes()) {
// We advance the main_iter by the length of the boundary, and the remaining hyphen
main_iter.nth(1 + boundary.len());
// We add it to the parts vector
parts.push(req.content.get(previous..idx).ok_or_else(|| Error::ExtractionBR(format!("internal error 1")))?);
previous = idx + 2 + boundary.len();
}
}
}
// Else, we do nothing
} else {
break;
}
}
// The first token needs to contain nothing
if parts.len() > 0 && parts[0].is_empty() {
parts.drain(0..1);
} else {
return Err(Error::ExtractionBR(format!("the content of the multipart request does not start properly")));
}
// If this multiform is properly formatted, then it needs to finish in `--\r\n`
if !(previous < req.content.len() && req.content.get(previous..req.content.len()).unwrap() == vec![b'-', b'-', b'\r', b'\n']) {
return Err(Error::ExtractionBR(format!("the content of the multipart request does not finish properly")));
}
// Now, for each token, we will remove the first and last 2 characters, which must be `\r\n`
for (idx, part) in parts.iter_mut().enumerate() {
if part.len() < 4 || part.get(0..2) != Some(&[b'\r', b'\n']) || part.get(part.len()-2..part.len()) != Some(&[b'\r', b'\n']) {
return Err(Error::ExtractionBR(format!("part {} of the multipart is not properly finished or started", idx)));
}
*part = part.get(2..part.len()-2).ok_or_else(|| Error::ExtractionBR(format!("internal error 2")))?;
}
// File holder
let mut raw_files = HashMap::new();
// Now, we will turn each part into a file
for part in parts {
let secondary_iter = part.iter().zip(part.iter().skip(2)).enumerate();
let mut split_index = None;
for (idx, (a, b)) in secondary_iter {
if a==b && b==&b'\n' && idx > 0 && part[idx-1] == b'\r' && part[idx+1] == b'\r' {
split_index = Some(idx);
break;
}
}
let split_index = split_index.ok_or(Error::ExtractionBR(format!("no end of inner-header was found for multipart")))?;
// We split one character before, because of the `\r`. This operation is safe, due to the secondary_iter search
let (inner_header, inner_content) = part.split_at(split_index - 1);
// The header needs to be a string
let inner_header = String::from_utf8(inner_header.to_vec()).map_err(|e| Error::ExtractionBR(format!("incorrect inner header format, {}", e)))?;
// We have to remove the `\r\n\r\n` that is at the beginning of the remaining bytes
let (_, inner_content) = inner_content.split_at(4);
let mut file = File {
name: "".into(),
filename: None,
content_type: None,
content: inner_content.to_vec()
};
let mut name_set = false;
for line in inner_header.split("\r\n") {
if let Some((tag, details)) = line.split_once(": ") {
match tag {
"Content-Disposition" => {
let mut token_iter = details.split("; ");
let mut pairs = HashMap::new();
// The first token needs to be "form-data"
if let Some(form_data_candidate) = token_iter.next() {
if form_data_candidate != "form-data" {
return Err(Error::ExtractionBR(format!("each document in multiform must be form-data content type")))
}
for remaining_token in token_iter {
if let Some((key, value)) = remaining_token.split_once("=") {
pairs.insert(key, value);
}
}
file.name = pairs.get("name").ok_or_else(|| Error::ExtractionBR(format!("a name for the multipart was not found")))?.to_string();
file.filename = pairs.get("filename").map(|v| {
if v.len() > 2 {
v[1..v.len()-1].to_string()
} else {
v.to_string()
}
});
name_set = true;
} else {
return Err(Error::ExtractionBR(format!("Content-Disposition header seems to be empty")))
}
},
"Content-Type" => {
file.content_type = Some(details.into());
},
_ => ()
}
} else {
return Err(Error::ExtractionBR(format!("malformed header")))
}
}
if !name_set {
return Err(Error::ExtractionBR(format!("a component of the multipart was found to have no name")));
}
raw_files.insert(file.name.clone(), file);
}
Ok(Multipart {
raw_files
})
} else {
Err(Error::ExtractionBR(format!("boundary tag was not found")))
}
} else {
Err(Error::ExtractionBR(format!("the boundary should be specified as `boundary=???`")))
}
} else {
Err(Error::ExtractionBR(format!("multipart content-type must be multipart/form-data (received `{}`)", multipart_tag)))
}
} else {
Err(Error::ExtractionBR(format!("multipart content-type requires the multipart/form-data tag, and a boundary")))
}
} else {
Err(Error::ExtractionBR(format!("multipart request requires the content-type header")))
}
}
}