Struct sequoia_openpgp::cert::CertParser

pub struct CertParser<'a> { /* private fields */ }

An iterator over a sequence of certificates, i.e., an OpenPGP keyring.

The source of packets is a fallible iterator over Packets. In this way, it is possible to propagate parse errors.

A CertParser returns each TPK or TSK that it encounters. Note: if you don’t actually need all of the certificates, it is usually faster to use a RawCertParser and only fully parse and canonicalize those certificates that are relevant.

A CertParser’s behavior can be modeled using a simple state machine.

In the first and initial state, it looks for the start of a certificate, a Public Key packet or a Secret Key packet. When it encounters such a packet it buffers it, and transitions to the second state. Any other packet or an error causes it to emit an error and stay in the same state. When the source of packets is exhausted, it enters the End state.

In the second state, it looks for packets that belong to a certificate’s body. If it encounters a valid body packet, then it buffers it and stays in the same state. If it encounters the start of a certificate, then it emits the buffered certificate, buffers the packet, and stays in the same state. If it encounters an invalid packet (e.g., a Literal Data packet), it emits two items, the buffered certificate, and an error, and then it transitions back to the initial state. When the source of packets is exhausted, it emits the buffered certificate and enters the end state.

In the end state, it emits None.

                      Invalid Packet / Error
                    ,------------------------.
                    v                        |
   Not a      +---------+                +---------+
   Start  .-> | Looking | -------------> | Looking | <-. Cert
 of Cert  |   |   for   |     Start      |   for   |   | Body
  Packet  |   |  Start  |    of Cert     |  Cert   |   | Packet
 / Error  `-- | of Cert |     Packet     |  Body   | --'
              +---------+            .-> +---------+
                   |                 |      |  |
                   |                 `------'  |
                   |    Start of Cert Packet   |
                   |                           |
               EOF |         +-----+           | EOF
                    `------> | End | <---------'
                             +-----+
                              |  ^
                              `--'

The parser does not recurse into containers, thus when it encounters a container like a Compressed Data Packet, it will return an error even if the container contains a valid certificate.

The parser considers unknown packets to be valid body packets. (In a Cert, these show up as Unknown components.) The goal is to provide some future compatibility.

Examples

Print information about all certificates in a keyring:

use sequoia_openpgp as openpgp;
use openpgp::parse::Parse;
use openpgp::parse::PacketParser;
use openpgp::cert::prelude::*;

let ppr = PacketParser::from_bytes(&keyring)?;
for certo in CertParser::from(ppr) {
    match certo {
        Ok(cert) => {
            println!("Key: {}", cert.fingerprint());
            for ua in cert.userids() {
                println!("  User ID: {}", ua.userid());
            }
        }
        Err(err) => {
            eprintln!("Error reading keyring: {}", err);
        }
    }
}

When an invalid packet is encountered, an error is returned and parsing continues:

use sequoia_openpgp as openpgp;
use openpgp::cert::prelude::*;
use openpgp::packet::prelude::*;
use openpgp::types::DataFormat;

let mut lit = Literal::new(DataFormat::Text);
lit.set_body(b"test".to_vec());

let (alice, _) =
      CertBuilder::general_purpose(None, Some("alice@example.org"))
      .generate()?;
let (bob, _) =
      CertBuilder::general_purpose(None, Some("bob@example.org"))
      .generate()?;

let mut packets : Vec<Packet> = Vec::new();
packets.extend(alice.clone());
packets.push(lit.clone().into());
packets.push(lit.clone().into());
packets.extend(bob.clone());

let r : Vec<Result<Cert>> = CertParser::from(packets).collect();
assert_eq!(r.len(), 4);
assert_eq!(r[0].as_ref().unwrap().fingerprint(), alice.fingerprint());
assert!(r[1].is_err());
assert!(r[2].is_err());
assert_eq!(r[3].as_ref().unwrap().fingerprint(), bob.fingerprint());

Implementations

impl<'a> CertParser<'a>

pub fn from_iter<I, J>(iter: I) -> Self

where I: 'a + IntoIterator<Item = J>, J: 'a + Into<Result<Packet>>, <I as IntoIterator>::IntoIter: Send + Sync,

Creates a CertParser from a Result<Packet> iterator.

Note: because we implement From<Packet> for Result<Packet>, it is possible to pass in an iterator over Packets.

Examples

From a Vec<Packet>:

use sequoia_openpgp as openpgp;
use openpgp::cert::prelude::*;
use openpgp::packet::prelude::*;

for certo in CertParser::from_iter(packets) {
    match certo {
        Ok(cert) => {
            println!("Key: {}", cert.fingerprint());
            for ua in cert.userids() {
                println!("  User ID: {}", ua.userid());
            }
        }
        Err(err) => {
            eprintln!("Error reading keyring: {}", err);
        }
    }
}

pub fn unvalidated_cert_filter<F>(self, filter: F) -> Self

where F: Send + Sync + Fn(&Cert, bool) -> bool + 'a,

Filters the Certs prior to validation.

By default, the CertParser only returns valdiated Certs. Checking that a certificate’s self-signatures are valid, however, is computationally expensive, and not always necessary. For example, when looking for a small number of certificates in a large keyring, most certificates can be immediately discarded. That is, it is more efficient to filter, validate, and double check, than to validate and filter. (It is necessary to double check, because the check might have been on an invalid part. For example, if searching for a key with a particular Key ID, a matching key might not have any self signatures.)

If the CertParser gave out unvalidated Certs, and provided an interface to validate them, then the caller could implement this check-validate-double-check pattern. Giving out unvalidated Certs, however, is dangerous: inevitably, a Cert will be used without having been validated in a context where it should have been.

This function avoids this class of bugs while still providing a mechanism to filter Certs prior to validation: the caller provides a callback that is invoked on the unvalidated Cert. If the callback returns true, then the parser validates the Cert, and invokes the callback a second time to make sure the Cert is really wanted. If the callback returns false, then the Cert is skipped.

Note: calling this function multiple times on a single CertParser will not replace the existing filter, but install multiple filters.

Examples

use sequoia_openpgp as openpgp;
use openpgp::cert::prelude::*;

for certr in CertParser::from(ppr)
    .unvalidated_cert_filter(|cert, _| {
        for component in cert.keys() {
            if component.key().keyid() == some_keyid {
                return true;
            }
        }
        false
    })
{
    match certr {
        Ok(cert) => {
            // The Cert contains the subkey.
        }
        Err(err) => {
            eprintln!("Error reading keyring: {}", err);
        }
    }
}

Trait Implementations

impl<'a> Default for CertParser<'a>

fn default() -> CertParser<'a>

Returns the “default value” for a type.

impl<'a> From<PacketParserResult<'a>> for CertParser<'a>

fn from(ppr: PacketParserResult<'a>) -> Self

Initializes a CertParser from a PacketParser.

impl<'a> From<Vec<Packet>> for CertParser<'a>

fn from(p: Vec<Packet>) -> CertParser<'a>

Converts to this type from the input type.

impl<'a> From<Vec<Result<Packet, Error>>> for CertParser<'a>

fn from(p: Vec<Result<Packet>>) -> CertParser<'a>

Converts to this type from the input type.

impl<'a> Iterator for CertParser<'a>

type Item = Result<Cert, Error>

The type of the elements being iterated over.

fn next(&mut self) -> Option<Self::Item>

Advances the iterator and returns the next value.

fn next_chunk<const N: usize>( &mut self, ) -> Result<[Self::Item; N], IntoIter<Self::Item, N>>

where Self: Sized,

🔬This is a nightly-only experimental API. (iter_next_chunk)

Advances the iterator and returns an array containing the next N values.

fn size_hint(&self) -> (usize, Option<usize>)

Returns the bounds on the remaining length of the iterator.

fn count(self) -> usize

where Self: Sized,

Consumes the iterator, counting the number of iterations and returning it.

fn last(self) -> Option<Self::Item>

where Self: Sized,

Consumes the iterator, returning the last element.

fn advance_by(&mut self, n: usize) -> Result<(), NonZero<usize>>

🔬This is a nightly-only experimental API. (iter_advance_by)

Advances the iterator by n elements.

fn nth(&mut self, n: usize) -> Option<Self::Item>

Returns the nth element of the iterator.

fn step_by(self, step: usize) -> StepBy<Self>

where Self: Sized,

Creates an iterator starting at the same point, but stepping by the given amount at each iteration.

fn chain<U>(self, other: U) -> Chain<Self, <U as IntoIterator>::IntoIter>

where Self: Sized, U: IntoIterator<Item = Self::Item>,

Takes two iterators and creates a new iterator over both in sequence.

fn zip<U>(self, other: U) -> Zip<Self, <U as IntoIterator>::IntoIter>

where Self: Sized, U: IntoIterator,

‘Zips up’ two iterators into a single iterator of pairs.

fn intersperse_with<G>(self, separator: G) -> IntersperseWith<Self, G>

where Self: Sized, G: FnMut() -> Self::Item,

🔬This is a nightly-only experimental API. (iter_intersperse)

Creates a new iterator which places an item generated by separator between adjacent items of the original iterator.

fn map<B, F>(self, f: F) -> Map<Self, F>

where Self: Sized, F: FnMut(Self::Item) -> B,

Takes a closure and creates an iterator which calls that closure on each element.

fn for_each<F>(self, f: F)

where Self: Sized, F: FnMut(Self::Item),

Calls a closure on each element of an iterator.

fn filter<P>(self, predicate: P) -> Filter<Self, P>

where Self: Sized, P: FnMut(&Self::Item) -> bool,

Creates an iterator which uses a closure to determine if an element should be yielded.

fn filter_map<B, F>(self, f: F) -> FilterMap<Self, F>

where Self: Sized, F: FnMut(Self::Item) -> Option<B>,

Creates an iterator that both filters and maps.

fn enumerate(self) -> Enumerate<Self>

where Self: Sized,

Creates an iterator which gives the current iteration count as well as the next value.

fn peekable(self) -> Peekable<Self>

where Self: Sized,

Creates an iterator which can use the peek and peek_mut methods to look at the next element of the iterator without consuming it. See their documentation for more information.

fn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P>

where Self: Sized, P: FnMut(&Self::Item) -> bool,

Creates an iterator that skips elements based on a predicate.

fn take_while<P>(self, predicate: P) -> TakeWhile<Self, P>

where Self: Sized, P: FnMut(&Self::Item) -> bool,

Creates an iterator that yields elements based on a predicate.

fn map_while<B, P>(self, predicate: P) -> MapWhile<Self, P>

where Self: Sized, P: FnMut(Self::Item) -> Option<B>,

Creates an iterator that both yields elements based on a predicate and maps.

fn skip(self, n: usize) -> Skip<Self>

where Self: Sized,

Creates an iterator that skips the first n elements.

fn take(self, n: usize) -> Take<Self>

where Self: Sized,

Creates an iterator that yields the first n elements, or fewer if the underlying iterator ends sooner.

fn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F>

where Self: Sized, F: FnMut(&mut St, Self::Item) -> Option<B>,

An iterator adapter which, like fold, holds internal state, but unlike fold, produces a new iterator.

fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F>

where Self: Sized, U: IntoIterator, F: FnMut(Self::Item) -> U,

Creates an iterator that works like map, but flattens nested structure.

fn map_windows<F, R, const N: usize>(self, f: F) -> MapWindows<Self, F, N>

where Self: Sized, F: FnMut(&[Self::Item; N]) -> R,

🔬This is a nightly-only experimental API. (iter_map_windows)

Calls the given function f for each contiguous window of size N over self and returns an iterator over the outputs of f. Like slice::windows(), the windows during mapping overlap as well.

fn fuse(self) -> Fuse<Self>

where Self: Sized,

Creates an iterator which ends after the first None.

fn inspect<F>(self, f: F) -> Inspect<Self, F>

where Self: Sized, F: FnMut(&Self::Item),

Does something with each element of an iterator, passing the value on.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Borrows an iterator, rather than consuming it.

fn collect<B>(self) -> B

where B: FromIterator<Self::Item>, Self: Sized,

Transforms an iterator into a collection.

fn collect_into<E>(self, collection: &mut E) -> &mut E

where E: Extend<Self::Item>, Self: Sized,

🔬This is a nightly-only experimental API. (iter_collect_into)

Collects all the items from an iterator into a collection.

fn partition<B, F>(self, f: F) -> (B, B)

where Self: Sized, B: Default + Extend<Self::Item>, F: FnMut(&Self::Item) -> bool,

Consumes an iterator, creating two collections from it.

fn is_partitioned<P>(self, predicate: P) -> bool

where Self: Sized, P: FnMut(Self::Item) -> bool,

🔬This is a nightly-only experimental API. (iter_is_partitioned)

Checks if the elements of this iterator are partitioned according to the given predicate, such that all those that return true precede all those that return false.

fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R

where Self: Sized, F: FnMut(B, Self::Item) -> R, R: Try<Output = B>,

An iterator method that applies a function as long as it returns successfully, producing a single, final value.

fn try_for_each<F, R>(&mut self, f: F) -> R

where Self: Sized, F: FnMut(Self::Item) -> R, R: Try<Output = ()>,

An iterator method that applies a fallible function to each item in the iterator, stopping at the first error and returning that error.

fn fold<B, F>(self, init: B, f: F) -> B

where Self: Sized, F: FnMut(B, Self::Item) -> B,

Folds every element into an accumulator by applying an operation, returning the final result.

fn reduce<F>(self, f: F) -> Option<Self::Item>

where Self: Sized, F: FnMut(Self::Item, Self::Item) -> Self::Item,

Reduces the elements to a single one, by repeatedly applying a reducing operation.

fn try_reduce<R>( &mut self, f: impl FnMut(Self::Item, Self::Item) -> R, ) -> <<R as Try>::Residual as Residual<Option<<R as Try>::Output>>>::TryType

where Self: Sized, R: Try<Output = Self::Item>, <R as Try>::Residual: Residual<Option<Self::Item>>,

🔬This is a nightly-only experimental API. (iterator_try_reduce)

Reduces the elements to a single one by repeatedly applying a reducing operation. If the closure returns a failure, the failure is propagated back to the caller immediately.

fn all<F>(&mut self, f: F) -> bool

where Self: Sized, F: FnMut(Self::Item) -> bool,

Tests if every element of the iterator matches a predicate.

fn any<F>(&mut self, f: F) -> bool

where Self: Sized, F: FnMut(Self::Item) -> bool,

Tests if any element of the iterator matches a predicate.

fn find<P>(&mut self, predicate: P) -> Option<Self::Item>

where Self: Sized, P: FnMut(&Self::Item) -> bool,

Searches for an element of an iterator that satisfies a predicate.

fn find_map<B, F>(&mut self, f: F) -> Option<B>

where Self: Sized, F: FnMut(Self::Item) -> Option<B>,

Applies function to the elements of iterator and returns the first non-none result.

fn try_find<R>( &mut self, f: impl FnMut(&Self::Item) -> R, ) -> <<R as Try>::Residual as Residual<Option<Self::Item>>>::TryType

where Self: Sized, R: Try<Output = bool>, <R as Try>::Residual: Residual<Option<Self::Item>>,

🔬This is a nightly-only experimental API. (try_find)

Applies function to the elements of iterator and returns the first true result or the first error.

fn position<P>(&mut self, predicate: P) -> Option<usize>

where Self: Sized, P: FnMut(Self::Item) -> bool,

Searches for an element in an iterator, returning its index.

fn max_by_key<B, F>(self, f: F) -> Option<Self::Item>

where B: Ord, Self: Sized, F: FnMut(&Self::Item) -> B,

Returns the element that gives the maximum value from the specified function.

fn max_by<F>(self, compare: F) -> Option<Self::Item>

where Self: Sized, F: FnMut(&Self::Item, &Self::Item) -> Ordering,

Returns the element that gives the maximum value with respect to the specified comparison function.

fn min_by_key<B, F>(self, f: F) -> Option<Self::Item>

where B: Ord, Self: Sized, F: FnMut(&Self::Item) -> B,

Returns the element that gives the minimum value from the specified function.

fn min_by<F>(self, compare: F) -> Option<Self::Item>

where Self: Sized, F: FnMut(&Self::Item, &Self::Item) -> Ordering,

Returns the element that gives the minimum value with respect to the specified comparison function.

fn unzip<A, B, FromA, FromB>(self) -> (FromA, FromB)

where FromA: Default + Extend<A>, FromB: Default + Extend<B>, Self: Sized + Iterator<Item = (A, B)>,

Converts an iterator of pairs into a pair of containers.

fn copied<'a, T>(self) -> Copied<Self>

where T: 'a + Copy, Self: Sized + Iterator<Item = &'a T>,

Creates an iterator which copies all of its elements.

fn cloned<'a, T>(self) -> Cloned<Self>

where T: 'a + Clone, Self: Sized + Iterator<Item = &'a T>,

Creates an iterator which clones all of its elements.

fn array_chunks<const N: usize>(self) -> ArrayChunks<Self, N>

where Self: Sized,

🔬This is a nightly-only experimental API. (iter_array_chunks)

Returns an iterator over N elements of the iterator at a time.

fn sum<S>(self) -> S

where Self: Sized, S: Sum<Self::Item>,

Sums the elements of an iterator.

fn product<P>(self) -> P

where Self: Sized, P: Product<Self::Item>,

Iterates over the entire iterator, multiplying all the elements

fn cmp_by<I, F>(self, other: I, cmp: F) -> Ordering

where Self: Sized, I: IntoIterator, F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Ordering,

🔬This is a nightly-only experimental API. (iter_order_by)

Lexicographically compares the elements of this Iterator with those of another with respect to the specified comparison function.

fn partial_cmp<I>(self, other: I) -> Option<Ordering>

where I: IntoIterator, Self::Item: PartialOrd<<I as IntoIterator>::Item>, Self: Sized,

Lexicographically compares the PartialOrd elements of this Iterator with those of another. The comparison works like short-circuit evaluation, returning a result without comparing the remaining elements. As soon as an order can be determined, the evaluation stops and a result is returned.

fn partial_cmp_by<I, F>(self, other: I, partial_cmp: F) -> Option<Ordering>

where Self: Sized, I: IntoIterator, F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Option<Ordering>,

🔬This is a nightly-only experimental API. (iter_order_by)

Lexicographically compares the elements of this Iterator with those of another with respect to the specified comparison function.

fn eq<I>(self, other: I) -> bool

where I: IntoIterator, Self::Item: PartialEq<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are equal to those of another.

fn eq_by<I, F>(self, other: I, eq: F) -> bool

where Self: Sized, I: IntoIterator, F: FnMut(Self::Item, <I as IntoIterator>::Item) -> bool,

🔬This is a nightly-only experimental API. (iter_order_by)

Determines if the elements of this Iterator are equal to those of another with respect to the specified equality function.

fn ne<I>(self, other: I) -> bool

where I: IntoIterator, Self::Item: PartialEq<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are not equal to those of another.

fn lt<I>(self, other: I) -> bool

where I: IntoIterator, Self::Item: PartialOrd<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are lexicographically less than those of another.

fn le<I>(self, other: I) -> bool

where I: IntoIterator, Self::Item: PartialOrd<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are lexicographically less or equal to those of another.

fn gt<I>(self, other: I) -> bool

where I: IntoIterator, Self::Item: PartialOrd<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are lexicographically greater than those of another.

fn ge<I>(self, other: I) -> bool

where I: IntoIterator, Self::Item: PartialOrd<<I as IntoIterator>::Item>, Self: Sized,

Determines if the elements of this Iterator are lexicographically greater than or equal to those of another.

fn is_sorted_by<F>(self, compare: F) -> bool

where Self: Sized, F: FnMut(&Self::Item, &Self::Item) -> bool,

🔬This is a nightly-only experimental API. (is_sorted)

Checks if the elements of this iterator are sorted using the given comparator function.

fn is_sorted_by_key<F, K>(self, f: F) -> bool

where Self: Sized, F: FnMut(Self::Item) -> K, K: PartialOrd,

🔬This is a nightly-only experimental API. (is_sorted)

Checks if the elements of this iterator are sorted using the given key extraction function.

impl<'a> Parse<'a, CertParser<'a>> for CertParser<'a>

fn from_buffered_reader<R>(reader: R) -> Result<CertParser<'a>>

where R: BufferedReader<Cookie> + 'a,

Initializes a CertParser from a BufferedReader.

fn from_reader<R: 'a + Read + Send + Sync>(reader: R) -> Result<Self>

Initializes a CertParser from a Reader.

fn from_file<P: AsRef<Path>>(path: P) -> Result<Self>

Initializes a CertParser from a File.

fn from_bytes<D: AsRef<[u8]> + ?Sized + Send + Sync>( data: &'a D, ) -> Result<Self>

Initializes a CertParser from a byte string.