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|
use std::str::FromStr;
/// The content part of a file that fills in a template.
pub struct Templated {
pub frontmatter: Frontmatter,
pub content: String,
}
impl FromStr for Templated {
type Err = TemplateError;
fn from_str(raw: &str) -> Result<Self, Self::Err> {
let (front, content) = match raw.strip_prefix("---\n") {
None => return Err(TemplateError::MissingFrontmatter),
Some(no_start) => match no_start.split_once("\n---\n") {
None => return Err(TemplateError::MissingFrontmatter),
Some((front, content)) => (front, content),
},
};
Ok(Self {
frontmatter: front.parse()?,
content: content.to_owned(),
})
}
}
pub struct Frontmatter {
entries: Vec<(String, String)>,
}
impl FromStr for Frontmatter {
type Err = TemplateError;
fn from_str(raw: &str) -> Result<Self, Self::Err> {
let mut entries = vec![];
for line in raw.lines() {
let trimmed = line.trim();
if trimmed.is_empty() || trimmed.starts_with('#') {
// Skip over blank lines and comments
continue;
}
let (key, value) = match trimmed.split_once('=') {
None => {
return Err(TemplateError::MalformedFrontmatterEntry {
line: trimmed.to_owned(),
});
}
Some(tup) => tup,
};
entries.push((key.trim().to_owned(), value.trim().to_owned()))
}
Ok(Self { entries })
}
}
impl Frontmatter {
pub fn get(&self, key: &str) -> Option<&str> {
self.entries
.iter()
.find(|(k, _)| k == key)
.map(|(_, v)| v.as_str())
}
pub fn get_many(&self, key: &str) -> Vec<&str> {
// this could probably be a filter_map() but the explicit filter and
// then map seems cleaner
self.entries
.iter()
.filter(|(k, _)| k == key)
.map(|(_, v)| v.as_str())
.collect()
}
}
#[derive(Debug, snafu::Snafu)]
pub enum TemplateError {
#[snafu(display("file is missing the frontmatter"))]
MissingFrontmatter,
#[snafu(display("the frontmatter entry is malformed: {line}"))]
MalformedFrontmatterEntry { line: String },
}
#[cfg(test)]
mod test {
use std::str::FromStr;
use crate::templated::{Frontmatter, Templated};
#[test]
fn frontmatter_parse() {
let frntmtr = "key=value\nkey2=value2";
assert!(Frontmatter::from_str(frntmtr).is_ok())
}
#[test]
fn frontmatter_fails_on_invalid_line() {
let front = "key1=value1\nincorrect line";
assert!(Frontmatter::from_str(front).is_err())
}
#[test]
fn templated_parse() {
let tempalted = "---\ntitle=Title!\n---\nContent line!";
assert!(Templated::from_str(tempalted).is_ok())
}
#[test]
fn templated_doesnt_eat_frontmatter_line() {
let templated = "---\ntitle=Title---\nContent";
assert!(Templated::from_str(templated).is_err());
}
#[test]
fn templated_parses_correct() {
let raw = "---\ntitle=Title!\n---\n<p>Paragraph!</p>";
let tmpl = Templated::from_str(raw).unwrap();
assert_eq!(tmpl.frontmatter.get("title").unwrap(), "Title!");
assert_eq!(tmpl.content, "<p>Paragraph!</p>")
}
}
|