Add CLI option -f, --file to read from file (#12)

`-` will act like an alias for `-f -`

Author: sayanarijit

Cargo.lock

@@ -1,6 +1,6 @@
 [package]
 name = "jf"
-version = "0.6.0"
+version = "0.6.1"
 edition = "2021"
 authors = ["Arijit Basu <[email protected]>"]
 description = 'A small utility to safely format and print JSON objects in the commandline'

Cargo.toml

@@ -43,25 +43,25 @@ nix-env -f https://github.com/NixOS/nixpkgs/tarball/nixos-unstable -iA jf
 ### USAGE
 
 ```bash
-jf [OPTION]... [--] TEMPLATE [VALUE]... [NAME=VALUE]... [NAME@FILE]...
+  jf [OPTION]... [--] TEMPLATE [VALUE]... [NAME=VALUE]... [NAME@FILE]...
 ```
 
 ### OPTIONS
 
-| option        | help                                            |
-| ------------- | ----------------------------------------------- |
-| -             | pass template via stdin                         |
-| --            | stop parsing CLI options                        |
-| -r, --raw     | print the raw rendered value without formatting |
-| -p, --pretty  | pretty print the JSON formatted output          |
-| -y, --yaml    | print the output as YAML instead of JSON        |
-| -h, --help    | print this help message                         |
-| -v, --version | print the version number                        |
+| option        | help                                               |
+| ------------- | -------------------------------------------------- |
+| -             | alias for `-f -`, i.e. read template from stdin    |
+| --            | stop parsing CLI options                           |
+| -r, --raw     | print the raw rendered value without formatting    |
+| -p, --pretty  | pretty print the JSON formatted output             |
+| -y, --yaml    | print the output as YAML instead of JSON           |
+| -h, --help    | print this help message                            |
+| -v, --version | print the version number                           |
+| -f, --file    | treat the template argument as a file to read from |
 
 ### TEMPLATE
 
-A template is a string that should render into valid YAML. It can contain the
-following placeholders:
+Template should render into valid YAML. It can contain the following placeholders:
 
 - `%%` a literal `%` character
 - `%s` `%q` read positional argument

README.md

@@ -8,7 +8,7 @@ jf [OPTION]\.\.\. [--] TEMPLATE [VALUE]\.\.\. [NAME=VALUE]\.\.\. [NAME@FILE]\.\.
 .TP
 .B
 -
-pass template via stdin
+alias for `\fB-f\fP -`, i.e. read template from stdin
 .TP
 .B
 --
@@ -33,10 +33,13 @@ print this help message
 .B
 \fB-v\fP, \fB--version\fP
 print the version number
+.TP
+.B
+\fB-f\fP, \fB--file\fP
+treat the template argument as a file to read from
 .SH TEMPLATE
 
-A template is a string that should render into valid YAML. It can contain the
-following placeholders:
+Template should render into valid YAML. It can contain the following placeholders:
 .TP
 .B
 `%%`

assets/jf.1

@@ -1,8 +1,8 @@
 use crate as jf;
 use crate::VERSION;
 use std::env::Args;
-use std::io;
-use std::iter::{Peekable, Skip};
+use std::iter::Skip;
+use std::{fs, io};
 
 #[derive(Debug)]
 pub enum Format {
@@ -16,60 +16,81 @@ pub enum Format {
 pub enum Cli {
     Help,
     Version,
-    Format(Format, Peekable<Skip<Args>>),
+    Format(Format, Option<String>, Skip<Args>),
 }
 
 impl Cli {
-    pub fn parse() -> Result<Self, jf::Error> {
+    pub fn parse() -> jf::Result<Self> {
         let mut format = Format::Json;
-        let mut args = std::env::args().skip(1).peekable();
+        let mut template: Option<String> = None;
+        let mut args = std::env::args().skip(1);
+        let mut is_file = false;
 
-        while let Some(arg) = args.peek_mut() {
+        while let Some(arg) = args.next() {
             match arg.as_str() {
                 "-h" | "--help" => return Ok(Self::Help),
                 "-v" | "--version" => return Ok(Self::Version),
                 "-r" | "--raw" => {
                     format = Format::Raw;
-                    args.next();
                 }
                 "-p" | "--pretty" => {
                     format = Format::PrettyJson;
-                    args.next();
                 }
                 "-y" | "--yaml" => {
                     format = Format::Yaml;
-                    args.next();
+                }
+                "-f" | "--file" => {
+                    is_file = true;
                 }
                 "-" => {
-                    *arg = io::read_to_string(io::stdin().lock())?;
+                    is_file = false;
+                    template = Some(io::read_to_string(io::stdin().lock())?);
                     break;
                 }
                 "--" => {
-                    args.next();
                     break;
                 }
                 a if a.starts_with('-') => {
                     return Err(format!("invalid argument {a}, try -h or --help")
                         .as_str()
                         .into())
                 }
-                _ => break,
+                _ => {
+                    template = Some(arg);
+                    break;
+                }
             }
         }
 
-        Ok(Self::Format(format, args))
+        if template.is_none() {
+            template = args.next()
+        }
+
+        if is_file {
+            if let Some(tmpl) = template.as_mut() {
+                *tmpl = fs::read_to_string(&tmpl)?;
+            }
+        }
+
+        Ok(Self::Format(format, template, args))
     }
 
     pub fn process(self) -> Result<String, jf::Error> {
         match self {
             Self::Help => Ok(jf::USAGE.into()),
             Self::Version => Ok(format!("jf {VERSION}")),
-            Self::Format(Format::Raw, args) => jf::render(args.map(Into::into)),
-            Self::Format(Format::Json, args) => jf::format(args.map(Into::into)),
-            Self::Format(Format::PrettyJson, args) => {
-                jf::format_pretty(args.map(Into::into))
+            Self::Format(Format::Raw, template, args) => {
+                jf::render(template.iter().map(Into::into).chain(args.map(Into::into)))
+            }
+            Self::Format(Format::Json, template, args) => {
+                jf::format(template.iter().map(Into::into).chain(args.map(Into::into)))
             }
-            Self::Format(Format::Yaml, args) => jf::format_yaml(args.map(Into::into)),
+            Self::Format(Format::PrettyJson, template, args) => jf::format_pretty(
+                template.iter().map(Into::into).chain(args.map(Into::into)),
+            ),
+            Self::Format(Format::Yaml, template, args) => jf::format_yaml(
+                template.iter().map(Into::into).chain(args.map(Into::into)),
+            ),
         }
     }
 }

src/cli.rs

@@ -5,16 +5,16 @@
 /// To handle also the CLI options, use the `jf::cli` module.
 pub mod cli;
 pub mod error;
+pub use error::{Error, Result};
 pub use serde_json as json;
 pub use serde_yaml as yaml;
 
-use crate::error::{Error, Result};
 use std::io::BufRead;
 use std::{borrow::Cow, collections::HashMap};
 use std::{fs, io};
 
 pub const VERSION: &str = env!("CARGO_PKG_VERSION");
-pub const USAGE: &str = include_str!("./usage.txt");
+pub const USAGE: &str = include_str!("usage.txt");
 
 fn read_to_string<S>(path: &str, stdin: &mut S) -> Result<String>
 where

src/lib.rs

@@ -4,18 +4,18 @@ USAGE
 
 OPTIONS
 
-  -              pass template via stdin
+  -              alias for `-f -`, i.e. read template from stdin
   --             stop parsing CLI options
   -r, --raw      print the raw rendered value without formatting
   -p, --pretty   pretty print the JSON formatted output
   -y, --yaml     print the output as YAML instead of JSON
   -h, --help     print this help message
   -v, --version  print the version number
+  -f, --file     treat the template argument as a file to read from
 
 TEMPLATE
 
-  A template is a string that should render into valid YAML. It can contain the
-  following placeholders:
+  Template should render into valid YAML. It can contain the following placeholders:
 
   `%%`                                    a literal `%` character
   `%s`                `%q`                read positional argument