Jeffrey Finkelstein
badc887606
Simulate greedy parsing of an absolute datetime in the prefix of a string before parsing a subsequent time delta in the suffix of the string. This does not change the behavior of `parse_datetime`, it just prepares the code for a future change that allows parsing both the absolute datetime and the time delta from the same string. Greedy parsing is implemented by iterating over a list of patterns in decreasing order of length so that longer patterns are tried before shorter patterns. This guarantees that if there is an absolute datetime present at the beginning of the string, then it will definitely be parsed and the remaining part of the string is assumed to contain a time delta.
parse_datetime
A Rust crate for parsing human-readable relative time strings and human-readable datetime strings and converting them to a DateTime.
Features
- Parses a variety of human-readable and standard time formats.
- Supports positive and negative durations.
- Allows for chaining time units (e.g., "1 hour 2 minutes" or "2 days and 2 hours").
- Calculate durations relative to a specified date.
- Relies on Chrono
Usage
Add this to your Cargo.toml:
[dependencies]
parse_datetime = "0.6.0"
Then, import the crate and use the parse_datetime_at_date function:
use chrono::{Duration, Local};
use parse_datetime::parse_datetime_at_date;
let now = Local::now();
let after = parse_datetime_at_date(now, "+3 days");
assert_eq!(
(now + Duration::days(3)).naive_utc(),
after.unwrap().naive_utc()
);
For DateTime parsing, import the parse_datetime function:
use parse_datetime::parse_datetime;
use chrono::{Local, TimeZone};
let dt = parse_datetime("2021-02-14 06:37:47");
assert_eq!(dt.unwrap(), Local.with_ymd_and_hms(2021, 2, 14, 6, 37, 47).unwrap());
Supported Formats
The parse_datetime and parse_datetime_at_date functions support absolute datetime and the following relative times:
numunit(e.g., "-1 hour", "+3 days")unit(e.g., "hour", "day")- "now" or "today"
- "yesterday"
- "tomorrow"
- use "ago" for the past
- use "next" or "last" with
unit(e.g., "next week", "last year") - combined units with "and" or "," (e.g., "2 years and 1 month", "1 day, 2 hours" or "2 weeks 1 second")
- unix timestamps (for example "@0" "@1344000")
num can be a positive or negative integer.
unit can be one of the following: "fortnight", "week", "day", "hour", "minute", "min", "second", "sec" and their plural forms.
Return Values
parse_datetime and parse_datetime_at_date
The parse_datetime and parse_datetime_at_date function return:
Ok(DateTime<FixedOffset>)- If the input string can be parsed as a datetimeErr(ParseDateTimeError::InvalidInput)- If the input string cannot be parsed
Fuzzer
To run the fuzzer:
$ cd fuzz
$ cargo install cargo-fuzz
$ cargo +nightly fuzz run fuzz_parse_datetime
License
This project is licensed under the MIT License.
Note
At some point, this crate was called humantime_to_duration. It has been renamed to cover more cases.