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feat(storage): Implement DiskTokenStorage
DiskTokenStorage is a TokenStorage that stores its tokens in a JSON file on disk. That file can be read in later, and the tokens in it reused. (The idea for a cache file is from here: https://developers.google.com/drive/v3/web/quickstart/go)
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,198 @@ | ||
| /* | ||
| * partially (c) 2016 Google Inc. (Lewin Bormann, [email protected]) | ||
| * | ||
| * See project root for licensing information. | ||
| */ | ||
|
|
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| extern crate serde_json; | ||
|
|
||
| use std::collections::HashMap; | ||
| use std::hash::Hasher; | ||
| use std::error::Error; | ||
| use std::fmt; | ||
| use std::fs; | ||
| use std::io; | ||
| use std::io::{Read, Write}; | ||
|
|
||
| use common::Token; | ||
|
|
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| /// Implements a specialized storage to set and retrieve `Token` instances. | ||
| /// The `scope_hash` represents the signature of the scopes for which the given token | ||
| /// should be stored or retrieved. | ||
| /// For completeness, the underlying, sorted scopes are provided as well. They might be | ||
| /// useful for presentation to the user. | ||
| pub trait TokenStorage { | ||
| type Error: 'static + Error; | ||
|
|
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| /// If `token` is None, it is invalid or revoked and should be removed from storage. | ||
| /// Otherwise, it should be saved. | ||
| fn set(&mut self, | ||
| scope_hash: u64, | ||
| scopes: &Vec<&str>, | ||
| token: Option<Token>) | ||
| -> Result<(), Self::Error>; | ||
| /// A `None` result indicates that there is no token for the given scope_hash. | ||
| fn get(&self, scope_hash: u64, scopes: &Vec<&str>) -> Result<Option<Token>, Self::Error>; | ||
| } | ||
|
|
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| /// A storage that remembers nothing. | ||
| #[derive(Default)] | ||
| pub struct NullStorage; | ||
| #[derive(Debug)] | ||
| pub struct NullError; | ||
|
|
||
| impl Error for NullError { | ||
| fn description(&self) -> &str { | ||
| "NULL" | ||
| } | ||
| } | ||
|
|
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| impl fmt::Display for NullError { | ||
| fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> { | ||
| "NULL-ERROR".fmt(f) | ||
| } | ||
| } | ||
|
|
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| impl TokenStorage for NullStorage { | ||
| type Error = NullError; | ||
| fn set(&mut self, _: u64, _: &Vec<&str>, _: Option<Token>) -> Result<(), NullError> { | ||
| Ok(()) | ||
| } | ||
| fn get(&self, _: u64, _: &Vec<&str>) -> Result<Option<Token>, NullError> { | ||
| Ok(None) | ||
| } | ||
| } | ||
|
|
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| /// A storage that remembers values for one session only. | ||
| #[derive(Default)] | ||
| pub struct MemoryStorage { | ||
| pub tokens: HashMap<u64, Token>, | ||
| } | ||
|
|
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| impl TokenStorage for MemoryStorage { | ||
| type Error = NullError; | ||
|
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| fn set(&mut self, | ||
| scope_hash: u64, | ||
| _: &Vec<&str>, | ||
| token: Option<Token>) | ||
| -> Result<(), NullError> { | ||
| match token { | ||
| Some(t) => self.tokens.insert(scope_hash, t), | ||
| None => self.tokens.remove(&scope_hash), | ||
| }; | ||
| Ok(()) | ||
| } | ||
|
|
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| fn get(&self, scope_hash: u64, _: &Vec<&str>) -> Result<Option<Token>, NullError> { | ||
| match self.tokens.get(&scope_hash) { | ||
| Some(t) => Ok(Some(t.clone())), | ||
| None => Ok(None), | ||
| } | ||
| } | ||
| } | ||
|
|
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| /// A single stored token. | ||
| #[derive(Serialize, Deserialize)] | ||
| struct JSONToken { | ||
| pub hash: u64, | ||
| pub token: Token, | ||
| } | ||
|
|
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| /// List of tokens in a JSON object | ||
| #[derive(Serialize, Deserialize)] | ||
| struct JSONTokens { | ||
| pub tokens: Vec<JSONToken>, | ||
| } | ||
|
|
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| /// Serializes tokens to a JSON file on disk. | ||
| #[derive(Default)] | ||
| pub struct DiskTokenStorage { | ||
| location: String, | ||
| tokens: HashMap<u64, Token>, | ||
| } | ||
|
|
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| impl DiskTokenStorage { | ||
| pub fn new(location: &String) -> DiskTokenStorage { | ||
| use std::fs; | ||
| let mut dts = DiskTokenStorage { | ||
| location: location.clone(), | ||
| tokens: HashMap::new(), | ||
| }; | ||
|
|
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| // best-effort | ||
| let _ = dts.load_from_file(); | ||
| dts | ||
| } | ||
|
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| fn load_from_file(&mut self) -> Result<(), io::Error> { | ||
| let mut f = try!(fs::OpenOptions::new().read(true).open(&self.location)); | ||
| let mut contents = String::new(); | ||
|
|
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| match f.read_to_string(&mut contents) { | ||
| Result::Err(e) => return Result::Err(e), | ||
| Result::Ok(_sz) => (), | ||
| } | ||
|
|
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| let tokens: JSONTokens; | ||
|
|
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| match serde_json::from_str(&contents) { | ||
| Result::Err(e) => return Result::Err(io::Error::new(io::ErrorKind::InvalidData, e)), | ||
| Result::Ok(t) => tokens = t, | ||
| } | ||
|
|
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| for t in tokens.tokens { | ||
| self.tokens.insert(t.hash, t.token); | ||
| } | ||
| return Result::Ok(()); | ||
| } | ||
|
|
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| pub fn dump_to_file(&mut self) -> Result<(), io::Error> { | ||
| let mut jsontokens = JSONTokens { tokens: Vec::new() }; | ||
|
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| for (hash, token) in self.tokens.iter() { | ||
| jsontokens.tokens.push(JSONToken { | ||
| hash: *hash, | ||
| token: token.clone(), | ||
| }); | ||
| } | ||
|
|
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| let serialized;; | ||
|
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| match serde_json::to_string(&jsontokens) { | ||
| Result::Err(e) => return Result::Err(io::Error::new(io::ErrorKind::InvalidData, e)), | ||
| Result::Ok(s) => serialized = s, | ||
| } | ||
|
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| let mut f = try!(fs::OpenOptions::new() | ||
| .create(true) | ||
| .write(true) | ||
| .truncate(true) | ||
| .open(&self.location)); | ||
| f.write(serialized.as_ref()).map(|_| ()) | ||
| } | ||
| } | ||
|
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| impl TokenStorage for DiskTokenStorage { | ||
| type Error = io::Error; | ||
| fn set(&mut self, | ||
| scope_hash: u64, | ||
| _: &Vec<&str>, | ||
| token: Option<Token>) | ||
| -> Result<(), Self::Error> { | ||
| match token { | ||
| None => { | ||
| self.tokens.remove(&scope_hash); | ||
| () | ||
| } | ||
| Some(t) => { | ||
| self.tokens.insert(scope_hash, t.clone()); | ||
| () | ||
| } | ||
| } | ||
| self.dump_to_file() | ||
| } | ||
| fn get(&self, scope_hash: u64, _: &Vec<&str>) -> Result<Option<Token>, Self::Error> { | ||
| Result::Ok(self.tokens.get(&scope_hash).map(|tok| tok.clone())) | ||
| } | ||
| } |