requestr_core/
template.rs

1extern crate regex;
2
3use regex::Regex;
4use std::collections::{HashMap, HashSet};
5
6#[derive(Debug, PartialEq)]
7pub struct Template {
8    pub src: String,
9    pub matches: Vec<(usize, usize)>,
10    pub names: HashSet<String>,
11}
12
13impl Template {
14    pub fn new(template: &str) -> Self {
15        let regex = Regex::new(r"\{\{\s*([^}\s]*)\s*\}\}").unwrap();
16
17        Template {
18            src: template.to_owned(),
19            matches: regex
20                .find_iter(template)
21                .map(|m| (m.start(), m.end()))
22                .collect(),
23            names: regex
24                .captures_iter(template)
25                .map(|cap| cap[1].to_string())
26                // .into_iter()
27                .collect(),
28        }
29    }
30
31    /// # Examples
32    /// ```
33    /// use std::collections::HashMap;
34    /// use requestr_core::Template;
35    ///
36    /// let template = Template::new("Hi, my name is {{ name }} and I'm a {{ lang }} developer.");
37    ///
38    /// let mut args: HashMap<String, String> = HashMap::new();
39    /// args.insert("name".to_string(), "Stefan".to_string());
40    /// args.insert("lang".to_string(), "Scala".to_string());
41    /// let s = template.render(&args);
42    ///
43    /// assert_eq!(s, "Hi, my name is Stefan and I'm a Scala developer.");
44    /// ```
45    ///
46    /// ```
47    /// use std::collections::HashMap;
48    /// use requestr_core::Template;
49    ///
50    /// let template = Template::new("Hi, my name is {{   name   }} and I'm a {{lang}} developer.");
51
52    /// let mut args: HashMap<String, String> = HashMap::new();
53    /// args.insert("name".to_string(), "undefined".to_string());
54    /// args.insert("lang".to_string(), "JavaScript".to_string());
55    /// let s = template.render(&args);
56    ///
57    /// assert_eq!(s, "Hi, my name is undefined and I'm a JavaScript developer.");
58    /// ```
59    pub fn render(&self, vals: &HashMap<String, String>) -> String {
60        let mut parts: Vec<&str> = vec![];
61        let template_str = &self.src;
62
63        // get index of first arg match or return a copy of the template if no args matched
64        let first = match self.matches.first() {
65            Some((start, _)) => *start,
66            _ => return template_str.clone(),
67        };
68
69        // copy from template start to first arg
70        if first > 0 {
71            parts.push(&template_str[0..first])
72        }
73
74        // keeps the index of the previous argument end
75        let mut prev_end: Option<usize> = None;
76
77        for (start, end) in self.matches.iter() {
78            // copy from previous argument end till current argument start
79            if let Some(last_end) = prev_end {
80                parts.push(&template_str[last_end..*start])
81            }
82
83            // argument name with braces
84            let arg = &template_str[*start..*end];
85            // just the argument name
86            let arg_name = arg[2..arg.len() - 2].trim();
87
88            // if value passed for argument then append it, otherwise append original argument
89            // name with braces
90            match vals.get(arg_name) {
91                Some(s) => parts.push(s),
92                _ => parts.push(arg),
93            }
94
95            prev_end = Some(*end);
96        }
97
98        let template_len = template_str.len();
99        // if last arg end index isn't the end of the string then copy
100        // from last arg end till end of template string
101        if let Some(last_pos) = prev_end {
102            if last_pos < template_len {
103                parts.push(&template_str[last_pos..template_len])
104            }
105        }
106
107        parts.join("")
108    }
109}
requestr_core/template.rs

requestr_core/
template.rs
