Add API action to change parameters, downgrade deserialize on owned data

api/src/action/mod.rs

@@ -1,3 +1,4 @@
 pub mod download;
+pub mod params;
 pub mod password;
 pub mod upload;

api/src/action/params.rs

@@ -0,0 +1,315 @@
+// TODO: define redirect policy
+
+use reqwest::{Client, StatusCode};
+use reqwest::header::Authorization;
+
+use api::data::{
+    Error as DataError,
+    OwnedData,
+};
+use crypto::b64;
+use crypto::key_set::KeySet;
+use crypto::sig::signature_encoded;
+use ext::status_code::StatusCodeExt;
+use file::remote_file::RemoteFile;
+
+/// The name of the header that is used for the authentication nonce.
+const HEADER_AUTH_NONCE: &'static str = "WWW-Authenticate";
+
+/// The default download count.
+const PARAMS_DEFAULT_DOWNLOAD: u8 = 1;
+
+/// The minimum allowed number of downloads, enforced by the server.
+const PARAMS_DOWNLOAD_MIN: u8 = 1;
+
+/// The maximum (inclusive) allowed number of downloads,
+/// enforced by the server.
+const PARAMS_DOWNLOAD_MAX: u8 = 20;
+
+/// An action to set parameters for a shared file.
+pub struct Params<'a> {
+    /// The remote file to change the parameters for.
+    file: &'a RemoteFile,
+
+    /// The parameter data that is sent to the server.
+    params: ParamsData,
+
+    /// The authentication nonce.
+    /// May be an empty vector if the nonce is unknown.
+    nonce: Vec<u8>,
+}
+
+impl<'a> Params<'a> {
+    /// Construct a new parameters action for the given remote file.
+    pub fn new(
+        file: &'a RemoteFile,
+        params: ParamsData,
+        nonce: Option<Vec<u8>>,
+    ) -> Self {
+        Self {
+            file,
+            params,
+            nonce: nonce.unwrap_or(Vec::new()),
+        }
+    }
+
+    /// Invoke the parameters action.
+    pub fn invoke(mut self, client: &Client) -> Result<(), Error> {
+        // TODO: validate that the parameters object isn't empty
+
+        // Create a key set for the file
+        let key = KeySet::from(self.file, None);
+
+        // Fetch the authentication nonce if not set yet
+        if self.nonce.is_empty() {
+            self.nonce = self.fetch_auth_nonce(client)?;
+        }
+
+        // Compute a signature
+        let sig = signature_encoded(key.auth_key().unwrap(), &self.nonce)
+            .map_err(|_| PrepareError::ComputeSignature)?;
+
+        // TODO: can we remove this?
+        // // Derive a new authentication key
+        // key.derive_auth_password(self.password, &self.file.download_url(true));
+
+        // Wrap the parameters data
+        let data = OwnedData::from(self.params.clone(), &self.file)
+            .map_err(|err| -> PrepareError { err.into() })?;
+
+        // Send the request to change the parameters
+        self.change_params(client, data, sig)
+            .map_err(|err| err.into())
+    }
+
+    /// Fetch the authentication nonce for the file from the Send server.
+    fn fetch_auth_nonce(&self, client: &Client)
+        -> Result<Vec<u8>, AuthError>
+    {
+        // Get the download URL, and parse the nonce
+        let download_url = self.file.download_url(false);
+        let response = client.get(download_url)
+            .send()
+            .map_err(|_| AuthError::NonceReq)?;
+
+        // Validate the status code
+        let status = response.status();
+        if !status.is_success() {
+            // TODO: should we check here whether a 404 is returned?
+            // // Handle expired files
+            // if status == FILE_EXPIRED_STATUS {
+            //     return Err(Error::Expired);
+            // } else {
+            return Err(AuthError::NonceReqStatus(status, status.err_text()).into());
+            // }
+        }
+
+        // Get the authentication nonce
+        b64::decode(
+            response.headers()
+                .get_raw(HEADER_AUTH_NONCE)
+                .ok_or(AuthError::NoNonceHeader)?
+                .one()
+                .ok_or(AuthError::MalformedNonce)
+                .and_then(|line| String::from_utf8(line.to_vec())
+                    .map_err(|_| AuthError::MalformedNonce)
+                )?
+                .split_terminator(" ")
+                .skip(1)
+                .next()
+                .ok_or(AuthError::MalformedNonce)?
+        ).map_err(|_| AuthError::MalformedNonce.into())
+    }
+
+    /// Send the request for changing the parameters.
+    fn change_params(
+        &self,
+        client: &Client,
+        data: OwnedData<ParamsData>,
+        sig: String,
+    ) -> Result<(), ChangeError> {
+        // Get the params URL, and send the change
+        let url = self.file.api_params_url();
+        let response = client.post(url)
+            .json(&data)
+            .header(Authorization(
+                format!("send-v1 {}", sig)
+            ))
+            .send()
+            .map_err(|_| ChangeError::Request)?;
+
+        // Validate the status code
+        let status = response.status();
+        if !status.is_success() {
+            return Err(ChangeError::RequestStatus(status, status.err_text()).into());
+        }
+
+        Ok(())
+    }
+}
+
+/// The parameters data object, that is sent to the server.
+#[derive(Clone, Debug, Serialize)]
+pub struct ParamsData {
+    /// The number of times this file may be downloaded.
+    /// This value must be in the `(0,20)` bounds, as enforced by Send servers.
+    #[serde(rename = "dlimit")]
+    downloads: Option<u8>,
+}
+
+impl ParamsData {
+    /// Create a new parameters data object, with the given parameters.
+    // TODO: the downloads must be between bounds
+    pub fn from(downloads: Option<u8>) -> Self {
+        ParamsData {
+            downloads,
+        }
+    }
+
+    /// Set the maximum number of allowed downloads, after which the file
+    /// will be removed.
+    ///
+    /// `None` may be given, to keep this parameter as is.
+    ///
+    /// An error may be returned if the download value is out of the allowed
+    /// bound. These bounds are fixed and enforced by the server.
+    /// See `PARAMS_DOWNLOAD_MIN` and `PARAMS_DOWNLOAD_MAX`.
+    pub fn set_downloads(&mut self, downloads: Option<u8>)
+        -> Result<(), ParamsDataError>
+    {
+        // Check the download bounds
+        if let Some(d) = downloads {
+            if d < PARAMS_DOWNLOAD_MIN || d > PARAMS_DOWNLOAD_MAX {
+                return Err(ParamsDataError::DownloadBounds);
+            }
+        }
+
+        // Set the downloads
+        self.downloads = downloads;
+        Ok(())
+    }
+
+    /// Check whether this parameters object is empty,
+    /// and wouldn't change any parameter on the server when sent.
+    /// Sending an empty parameter data object would thus be useless.
+    pub fn is_empty(&self) -> bool {
+        self.downloads.is_none()
+    }
+}
+
+impl Default for ParamsData {
+    fn default() -> ParamsData {
+        ParamsData {
+            downloads: Some(PARAMS_DEFAULT_DOWNLOAD),
+        }
+    }
+}
+
+#[derive(Fail, Debug)]
+pub enum Error {
+    /// An error occurred while preparing the action.
+    #[fail(display = "Failed to prepare setting the parameters")]
+    Prepare(#[cause] PrepareError),
+
+    // /// The given Send file has expired, or did never exist in the first place.
+    // /// Therefore the file could not be downloaded.
+    // #[fail(display = "The file has expired or did never exist")]
+    // Expired,
+
+    /// An error has occurred while sending the parameter change request to
+    /// the server.
+    #[fail(display = "Failed to send the parameter change request")]
+    Change(#[cause] ChangeError),
+}
+
+impl From<PrepareError> for Error {
+    fn from(err: PrepareError) -> Error {
+        Error::Prepare(err)
+    }
+}
+
+impl From<AuthError> for Error {
+    fn from(err: AuthError) -> Error {
+        PrepareError::Auth(err).into()
+    }
+}
+
+impl From<ChangeError> for Error {
+    fn from(err: ChangeError) -> Error {
+        Error::Change(err)
+    }
+}
+
+#[derive(Debug, Fail)]
+pub enum ParamsDataError {
+    /// The number of downloads is invalid, as it was out of the allowed
+    /// bounds. See `PARAMS_DOWNLOAD_MIN` and `PARAMS_DOWNLOAD_MAX`.
+    // TODO: use bound values from constants, don't hardcode them here
+    #[fail(display = "Invalid number of downloads, must be between 1 and 20")]
+    DownloadBounds,
+
+    /// Some error occurred while trying to wrap the parameter data in an
+    /// owned object, which is required for authentication on the server.
+    /// The wrapped error further described the problem.
+    #[fail(display = "")]
+    Owned(#[cause] DataError),
+}
+
+#[derive(Fail, Debug)]
+pub enum PrepareError {
+    /// Failed authenticating, needed to change the parameters.
+    #[fail(display = "Failed to authenticate")]
+    Auth(#[cause] AuthError),
+
+    /// An error occurred while computing the cryptographic signature.
+    #[fail(display = "Failed to compute cryptographic signature")]
+    ComputeSignature,
+
+    /// An error occurred while building the parameter data that will be send
+    /// to the server.
+    #[fail(display = "Invalid parameters")]
+    ParamsData(#[cause] ParamsDataError),
+}
+
+impl From<DataError> for PrepareError {
+    fn from(err: DataError) -> PrepareError {
+        PrepareError::ParamsData(ParamsDataError::Owned(err))
+    }
+}
+
+#[derive(Fail, Debug)]
+pub enum AuthError {
+    /// Sending the request to gather the authentication encryption nonce
+    /// failed.
+    #[fail(display = "Failed to request authentication nonce")]
+    NonceReq,
+
+    /// The response for fetching the authentication encryption nonce
+    /// indicated an error and wasn't successful.
+    #[fail(display = "Bad HTTP response '{}' while requesting authentication nonce", _1)]
+    NonceReqStatus(StatusCode, String),
+
+    /// No authentication encryption nonce was included in the response
+    /// from the server, it was missing.
+    #[fail(display = "Missing authentication nonce in server response")]
+    NoNonceHeader,
+
+    /// The authentication encryption nonce from the response malformed or
+    /// empty.
+    /// Maybe the server responded with a new format that isn't supported yet
+    /// by this client.
+    #[fail(display = "Received malformed authentication nonce")]
+    MalformedNonce,
+}
+
+#[derive(Fail, Debug)]
+pub enum ChangeError {
+    /// Sending the request to change the parameters failed.
+    #[fail(display = "Failed to send parameter change request")]
+    Request,
+
+    /// The response for changing the parameters indicated an error and wasn't
+    /// successful.
+    #[fail(display = "Bad HTTP response '{}' while changing the parameters", _1)]
+    RequestStatus(StatusCode, String),
+}

api/src/action/password.rs

@@ -137,7 +137,7 @@ impl<'a> Password<'a> {
 
 /// The data object to send to the password endpoint,
 /// which sets the file password.
-#[derive(Debug, Serialize, Deserialize)]
+#[derive(Debug, Serialize)]
 struct PasswordData {
     /// The authentication key
     auth: String,

api/src/api/data.rs

@@ -1,12 +1,12 @@
-use serde::{Deserialize, Serialize};
+use serde::Serialize;
 
 use file::remote_file::RemoteFile;
 
 /// An owned data structure, that wraps generic data.
-/// This structure is used to send owned data to the Send server.  
+/// This structure is used to send owned data to the Send server.
 /// This owned data is authenticated using an `owner_token`,
-/// wwhich this structure manages.
+/// which this structure manages.
-#[derive(Debug, Serialize, Deserialize)]
+#[derive(Debug, Serialize)]
 pub struct OwnedData<D> {
     /// The owner token, used for request authentication purposes.
     owner_token: String,
@@ -16,9 +16,9 @@ pub struct OwnedData<D> {
     inner: D,
 }
 
-impl<'a, D> OwnedData<D>
+impl<D> OwnedData<D>
     where
-        D: Serialize + Deserialize<'a>,
+        D: Serialize,
 {
     /// Constructor.
     pub fn new(owner_token: String, inner: D) -> Self {

api/src/file/remote_file.rs

@@ -209,6 +209,16 @@ impl RemoteFile {
 
         url
     }
+
+    /// Get the API params URL of the file.
+    pub fn api_params_url(&self) -> Url {
+        // Get the share URL, and add the secret fragment
+        let mut url = self.url.clone();
+        url.set_path(format!("/api/params/{}", self.id).as_str());
+        url.set_fragment(None);
+
+        url
+    }
 }
 
 #[derive(Debug, Fail)]

api/src/lib.rs

@@ -6,12 +6,14 @@ extern crate failure_derive;
 extern crate mime_guess;
 extern crate openssl;
 pub extern crate reqwest;
+extern crate serde;
 #[macro_use]
 extern crate serde_derive;
 extern crate serde_json;
 pub extern crate url;
 
 pub mod action;
+mod api;
 pub mod crypto;
 mod ext;
 pub mod file;