add new template cmd

CHANGELOG.md

@@ -3817,7 +3817,7 @@ the response, the HTTP status code, and if its a cache hit.
 request the URL again. https://github.com/jqnatividad/qsv/pull/393
 
 ### Changed
-* `fetch`: fast defaults. Now tries to go as fast as possible, leveraging dynamic throttling (using RateLimit and Rety-After headers) 
+* `fetch`: fast defaults. Now tries to go as fast as possible, leveraging dynamic throttling (using RateLimit and Retry-After headers) 
 but aborting after 100 errors. Also added a separate error progress bar. https://github.com/jqnatividad/qsv/pull/388
 * Smarter `tojsonl`. Now scans CSV file and infers data types and uses the appropriate JSON data type https://github.com/jqnatividad/qsv/pull/389
 * `tojsonl` is also multithreaded https://github.com/jqnatividad/qsv/pull/392

Cargo.toml

@@ -140,6 +140,12 @@ local-encoding = { version = "0.2", optional = true }
 localzone = { version = "0.3", features = ["auto_validation"] }
 log = "0.4"
 mimalloc = { version = "0.1", default-features = false, optional = true }
+minijinja = { version = "2", features = [
+    "json",
+    "loop_controls",
+    "speedups",
+    "urlencode",
+] }
 mlua = { version = "0.10", features = [
     "luau",
     "luau-jit",

src/cmd/mod.rs

@@ -93,6 +93,8 @@ pub mod sqlp;
 pub mod stats;
 #[cfg(any(feature = "feature_capable", feature = "lite"))]
 pub mod table;
+#[cfg(feature = "feature_capable")]
+pub mod template;
 #[cfg(all(feature = "to", feature = "feature_capable"))]
 pub mod to;
 #[cfg(any(feature = "feature_capable", feature = "lite"))]

src/cmd/template.rs

@@ -0,0 +1,175 @@
+static USAGE: &str = r#"
+Renders a template using CSV data with the minijinja template engine.
+https://docs.rs/minijinja/latest/minijinja/
+
+Each CSV row is used to populate the template, with column headers used as variable names.
+The template syntax follows the Jinja2 template language.
+
+Example template:
+    Dear {{ name }},
+    Your account balance is {{ balance | format_float(precision=2) }}.
+    Status: {{ if active }}Active{{ else }}Inactive{{ endif }}
+
+Usage:
+    qsv template [options] [--template <str> | --template-file <file>] [<input>] [<outdir> | --output <file>]
+    qsv template --help
+
+template arguments:
+    <input>                 The CSV file to read. If not given, input is read from STDIN.
+    <outdir>                The directory where the output files will be written.
+                            If it does not exist, it will be created.
+template options:
+    --template <str>        Template string to use (alternative to --template-file)
+    --template-file <file>  Template file to use
+    --outfilename <str>     Template string to use to create the filestem of the output 
+                            files to write to <outdir>. If set to ROWNO, the filestem
+                            is set to the current rowno of the record, padded with leading
+                            zeroes, with the ".txt" extension (e.g. 001.txt, 002.txt, etc.)
+                            [default: ROWNO]
+    -n, --no-headers        When set, the first row will not be interpreted
+                            as headers. Templates must use numeric 1-based indices
+                            with the "_c" prefix.(e.g. col1: {{_c1}} col2: {{_c2}})
+
+Common options:
+    -o, --output <file>     Write output to <file> instead of stdout
+    --delimiter <sep>       Field separator for reading CSV [default: ,]
+    -h, --help              Display this message
+"#;
+
+use std::{
+    fs,
+    io::{BufWriter, Write},
+};
+
+use minijinja::Environment;
+use serde::Deserialize;
+use serde_json::Value;
+
+use crate::{
+    config::{Config, Delimiter},
+    util, CliError, CliResult,
+};
+
+#[derive(Deserialize)]
+struct Args {
+    arg_input:     Option<String>,
+    arg_outdir:    Option<String>,
+    flag_template: Option<String>,
+
+    flag_template_file: Option<String>,
+    flag_output:        Option<String>,
+    flag_outfilename:   String,
+    flag_delimiter:     Option<Delimiter>,
+    flag_no_headers:    bool,
+}
+
+impl From<minijinja::Error> for CliError {
+    fn from(err: minijinja::Error) -> CliError {
+        CliError::Other(err.to_string())
+    }
+}
+
+pub fn run(argv: &[&str]) -> CliResult<()> {
+    let args: Args = util::get_args(USAGE, argv)?;
+
+    // Get template content
+    let template_content = match (args.flag_template_file, args.flag_template) {
+        (Some(path), None) => fs::read_to_string(path)?,
+        (None, Some(template)) => template,
+        _ => return fail_clierror!("Must provide either --template or --template-string"),
+    };
+
+    // Set up minijinja environment
+    let mut env = Environment::new();
+    env.add_template("template", &template_content)?;
+    let template = env.get_template("template")?;
+
+    // Set up CSV reader
+    let rconfig = Config::new(args.arg_input.as_ref())
+        .delimiter(args.flag_delimiter)
+        .no_headers(args.flag_no_headers);
+
+    let mut rdr = rconfig.reader()?;
+    let headers = if args.flag_no_headers {
+        csv::StringRecord::new()
+    } else {
+        rdr.headers()?.clone()
+    };
+
+    // Set up output handling
+    let output_to_dir = args.arg_outdir.is_some();
+    let mut row_number = 0_u64;
+    let mut rowcount = 0;
+
+    // Create filename environment once if needed
+    let filename_env = if output_to_dir && args.flag_outfilename != "ROWNO" {
+        let mut env = Environment::new();
+        env.add_template("filename", &args.flag_outfilename)?;
+        Some(env)
+    } else {
+        rowcount = util::count_rows(&rconfig)?;
+        None
+    };
+
+    let width = rowcount.to_string().len();
+
+    if output_to_dir {
+        fs::create_dir_all(args.arg_outdir.as_ref().unwrap())?;
+    }
+
+    let mut wtr = if output_to_dir {
+        None
+    } else {
+        Some(match args.flag_output {
+            Some(file) => Box::new(BufWriter::new(fs::File::create(file)?)) as Box<dyn Write>,
+            None => Box::new(BufWriter::new(std::io::stdout())) as Box<dyn Write>,
+        })
+    };
+
+    let mut curr_record = csv::StringRecord::new();
+
+    // Process each record
+    for record in rdr.records() {
+        row_number += 1;
+        curr_record.clone_from(&record?);
+        let mut context = serde_json::Map::with_capacity(curr_record.len());
+
+        if args.flag_no_headers {
+            // Use numeric indices
+            for (i, field) in curr_record.iter().enumerate() {
+                context.insert(format!("_c{}", i + 1), Value::String(field.to_string()));
+            }
+        } else {
+            // Use header names
+            for (header, field) in headers.iter().zip(curr_record.iter()) {
+                context.insert(header.to_string(), Value::String(field.to_string()));
+            }
+        }
+
+        // Render template with record data
+        let rendered = template.render(&context)?;
+
+        if output_to_dir {
+            let outfilename = if args.flag_outfilename == "ROWNO" {
+                format!("{row_number:0width$}.txt")
+            } else {
+                filename_env
+                    .as_ref()
+                    .unwrap()
+                    .get_template("filename")?
+                    .render(&context)?
+            };
+            let outpath = std::path::Path::new(args.arg_outdir.as_ref().unwrap()).join(outfilename);
+            let mut writer = BufWriter::new(fs::File::create(outpath)?);
+            write!(writer, "{rendered}")?;
+        } else if let Some(ref mut w) = wtr {
+            write!(w, "{rendered}")?;
+        }
+    }
+
+    if let Some(mut w) = wtr {
+        w.flush()?;
+    }
+
+    Ok(())
+}

src/main.rs

@@ -192,6 +192,7 @@ fn main() -> QsvExitCode {
     enabled_commands.push_str(
         "    stats       Infer data types and compute summary statistics
     table       Align CSV data into columns
+    template    Render templates using CSV data
     tojsonl     Convert CSV to newline-delimited JSON\n",
     );
 
@@ -393,6 +394,7 @@ enum Command {
     SqlP,
     Stats,
     Table,
+    Template,
     Transpose,
     #[cfg(all(feature = "to", feature = "feature_capable"))]
     To,
@@ -489,6 +491,7 @@ impl Command {
             Command::SqlP => cmd::sqlp::run(argv),
             Command::Stats => cmd::stats::run(argv),
             Command::Table => cmd::table::run(argv),
+            Command::Template => cmd::template::run(argv),
             Command::Transpose => cmd::transpose::run(argv),
             #[cfg(all(feature = "to", feature = "feature_capable"))]
             Command::To => cmd::to::run(argv),