Replace command parameters with values

To create a minimalistic parser, nom is used to identify and replace
parameters given in the command field.

For clarity the `action` field for hooks was renamed to `command`.

Cargo.lock

@@ -128,6 +128,18 @@ version = "1.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cf1de2fe8c75bc145a2f577add951f8134889b4795d47466a54a5c846d691693"
 
+[[package]]
+name = "bitvec"
+version = "0.19.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8942c8d352ae1838c9dda0b0ca2ab657696ef2232a20147cf1b30ae1a9cb4321"
+dependencies = [
+ "funty",
+ "radium",
+ "tap",
+ "wyz",
+]
+
 [[package]]
 name = "blake2b_simd"
 version = "0.5.11"
@@ -372,6 +384,12 @@ version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3dcaa9ae7725d12cdb85b3ad99a434db70b468c09ded17e012d86b5c1010f7a7"
 
+[[package]]
+name = "funty"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fed34cd105917e91daa4da6b3728c47b068749d6a62c59811f06ed2ac71d9da7"
+
 [[package]]
 name = "generic-array"
 version = "0.14.4"
@@ -582,6 +600,19 @@ version = "1.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "830d08ce1d1d941e6b30645f1a0eb5643013d835ce3779a5fc208261dbe10f55"
 
+[[package]]
+name = "lexical-core"
+version = "0.7.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "21f866863575d0e1d654fbeeabdc927292fdf862873dc3c96c6f753357e13374"
+dependencies = [
+ "arrayvec",
+ "bitflags",
+ "cfg-if 1.0.0",
+ "ryu",
+ "static_assertions",
+]
+
 [[package]]
 name = "libc"
 version = "0.2.90"
@@ -687,6 +718,19 @@ dependencies = [
  "winapi 0.3.9",
 ]
 
+[[package]]
+name = "nom"
+version = "6.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e7413f999671bd4745a7b624bd370a569fb6bc574b23c83a3c5ed2e453f3d5e2"
+dependencies = [
+ "bitvec",
+ "funty",
+ "lexical-core",
+ "memchr",
+ "version_check 0.9.3",
+]
+
 [[package]]
 name = "notify"
 version = "4.0.15"
@@ -808,6 +852,12 @@ dependencies = [
  "proc-macro2 1.0.24",
 ]
 
+[[package]]
+name = "radium"
+version = "0.5.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "941ba9d78d8e2f7ce474c015eea4d9c6d25b6a3327f9832ee29a4de27f91bbb8"
+
 [[package]]
 name = "rand"
 version = "0.8.3"
@@ -1102,6 +1152,12 @@ version = "0.4.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3015a7d0a5fd5105c91c3710d42f9ccf0abfb287d62206484dcc67f9569a6483"
 
+[[package]]
+name = "static_assertions"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a2eb9349b6444b326872e140eb1cf5e7c522154d69e7a0ffb0fb81c06b37543f"
+
 [[package]]
 name = "subtle"
 version = "2.4.0"
@@ -1130,6 +1186,12 @@ dependencies = [
  "unicode-xid 0.2.1",
 ]
 
+[[package]]
+name = "tap"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "55937e1799185b12863d447f42597ed69d9928686b8d88a1df17376a097d8369"
+
 [[package]]
 name = "termcolor"
 version = "1.1.2"
@@ -1300,6 +1362,7 @@ dependencies = [
  "dirs",
  "env_logger",
  "log 0.4.14",
+ "nom",
  "regex",
  "rocket",
  "rocket_contrib",
@@ -1381,6 +1444,12 @@ dependencies = [
  "winapi-build",
 ]
 
+[[package]]
+name = "wyz"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "85e60b0d1b5f99db2556934e21937020776a5d31520bf169e851ac44e6420214"
+
 [[package]]
 name = "yaml-rust"
 version = "0.4.5"

Cargo.toml

@@ -18,3 +18,4 @@ dirs = "3.0"
 anyhow = "1.0"
 log = "0.4"
 env_logger = "0.8"
+nom = "6"

README.md

@@ -1,8 +1,8 @@
 # Webhookey
-Webhookey basically is a webserver listening for requests as for
+Webhookey is a webserver listening for requests as for example sent by
-example sent as gitea's webhooks. Further, Webhookey allows you to
+gitea's webhooks. Further, Webhookey allows you to specifiy rules
-specifiy rules which are matched against the data received to trigger
+which are matched against the data received to trigger certain
-certain actions.
+actions.
 
 ## Build
 
@@ -55,12 +55,15 @@ Configuration syntax is YAML and has to be done in following order:
 
 Right now there is only the configuration parameter for hooks, here
 each hook has to be configured, It contains following fields:
-- action: optional string for the action to be executed when all
+- command: Optional string for a command to be executed when all
-  filters match
+  filters match. Pointers ([RFC
-- secrets: list of secrets
+  6901](https://tools.ietf.org/html/rfc6901)) to JSON fields may be
-- filters: list of filters
+  used to be replaced with data from the JSON data with `{{
+  /field/pointed/to }}`
+- secrets: List of secrets.
+- filters: List of filters.
 
-Each filter has to have following fields:
+Each filter must have following fields:
 - pointer: pointer to the JSON field according to [RFC
   6901](https://tools.ietf.org/html/rfc6901)
 - regex: regular expression which has to match the field pointed to by
@@ -88,3 +91,4 @@ Whereas `<config_dir>` depends on the platform:
 ### Authentication features
 ### Secure cookies?
 ## Parameterize fields
+## Use proptest or quickcheck for tests of parsers

config.yml

@@ -1,7 +1,7 @@
 ---
 hooks:
   hook1:
-    action: /usr/bin/local/script_xy.sh
+    command: /usr/bin/local/script_xy.sh {{ /field2/foo }} asdfasdf
     secrets:
       - secret_key_01
       - secret_key_02
@@ -10,7 +10,16 @@ hooks:
         pointer: /ref
         regex: refs/heads/master
   hook2:
-    action: /usr/bin/local/script_xyz.sh
+    command: /usr/bin/local/script_xy.sh asdfasdf
+    secrets:
+      - secret_key_01
+      - secret_key_02
+    filters:
+      match_ref:
+        pointer: /ref
+        regex: refs/heads/master
+  hook3:
+    command: /usr/bin/local/script_xyz.sh
     secrets:
       - secret_key03
     filters:

src/main.rs

@@ -2,6 +2,14 @@
 
 use anyhow::{anyhow, bail, Result};
 use log::{debug, info, trace, warn};
+use nom::{
+    branch::alt,
+    bytes::complete::{tag, take_until},
+    combinator::map_res,
+    multi::many0,
+    sequence::delimited,
+    Finish, IResult,
+};
 use regex::Regex;
 use rocket::{fairing::AdHoc, get, http::Status, post, routes, Response, State};
 use rocket_contrib::json::Json;
@@ -16,7 +24,7 @@ struct Config {
 
 #[derive(Debug, Deserialize, Serialize)]
 struct Hook {
-    action: Option<String>,
+    command: Option<String>,
     secrets: Vec<String>,
     filters: HashMap<String, Filter>,
 }
@@ -35,7 +43,34 @@ fn index() -> &'static str {
     "Hello, webhookey!"
 }
 
-fn execute_hook(name: &str, hook: &Hook, data: &serde_json::Value) -> Result<()> {
+fn replace_parameter(input: &str, data: &serde_json::Value) -> Result<String> {
+    let parse: IResult<&str, Vec<&str>> = many0(alt((
+        map_res(
+            delimited(tag("{{"), take_until("}}"), tag("}}")),
+            |param: &str| {
+                if let Some(value) = data.pointer(param.trim()) {
+                    if let Some(value) = value.as_str() {
+                        Ok(value)
+                    } else {
+                        bail!("Could not convert field `{}` to string", param.trim());
+                    }
+                } else {
+                    bail!("Could not find `{}` in received data", param.trim());
+                }
+            },
+        ),
+        take_until("{{"),
+    )))(input);
+
+    let (last, mut result) = parse
+        .finish()
+        .map_err(|e| anyhow!("Could not parse command: {}", e))?;
+    result.push(last);
+
+    Ok(result.join(""))
+}
+
+fn execute_hook<'a>(name: &'a str, hook: &'a Hook, data: &'a serde_json::Value) -> Result<()> {
     debug!("Running hook `{}`", name);
 
     for (filter_name, filter) in hook.filters.iter() {
@@ -59,25 +94,27 @@ fn execute_hook(name: &str, hook: &Hook, data: &serde_json::Value) -> Result<()>
         }
     }
 
-    if let Some(action) = &hook.action {
+    if let Some(command) = &hook.command {
-        info!("Execute `{}` from hook `{}`", action, name);
+        let command = replace_parameter(&command, data)?;
 
-        let action = action.split(' ').collect::<Vec<&str>>();
+        info!("Execute `{}` from hook `{}`", command, name);
 
-        let command = Command::new(action[0]).args(&action[1..]).output()?;
+        let command = command.split(' ').collect::<Vec<&str>>();
+
+        let exec_command = Command::new(&command[0]).args(&command[1..]).output()?;
 
         info!(
             "Command `{}` exited with return code: {}",
-            action[0], command.status
+            &command[0], &exec_command.status
         );
         debug!(
             "Output of command `{}` on stderr: {:?}",
-            action[0], &command.stderr
+            &command[0], &exec_command.stderr
         );
         trace!(
             "Output of command `{}` on stdout: {:?}",
-            action[0],
+            &command[0],
-            &command.stdout
+            &exec_command.stdout
         );
     }
 
@@ -134,7 +171,7 @@ fn get_config() -> Result<File> {
         if let Ok(config) = File::open(&path) {
             info!(
                 "Loading configuration from `{}`",
-                path.to_str().unwrap_or("path not printable"),
+                path.to_str().unwrap_or("<path unprintable>"),
             );
 
             return Ok(config);
@@ -171,6 +208,7 @@ fn main() -> Result<()> {
 mod tests {
     use super::*;
     use rocket::{http::ContentType, local::Client};
+    use serde_json::json;
 
     #[test]
     fn index() {
@@ -189,7 +227,7 @@ mod tests {
         hooks.insert(
             "test_hook".to_string(),
             Hook {
-                action: None,
+                command: None,
                 secrets: vec!["valid".to_string()],
                 filters: HashMap::new(),
             },
@@ -239,4 +277,65 @@ mod tests {
 
         assert_eq!(response.status(), Status::BadRequest);
     }
+
+    #[test]
+    fn parse_command() {
+        assert_eq!(
+            replace_parameter("command", &serde_json::Value::Null).unwrap(),
+            "command"
+        );
+
+        assert_eq!(
+            replace_parameter("    command", &serde_json::Value::Null).unwrap(),
+            "    command"
+        );
+
+        assert_eq!(
+            replace_parameter("command    ", &serde_json::Value::Null).unwrap(),
+            "command    "
+        );
+
+        assert_eq!(
+            replace_parameter("    command    ", &serde_json::Value::Null).unwrap(),
+            "    command    "
+        );
+
+        assert_eq!(
+            replace_parameter("command command    ", &serde_json::Value::Null).unwrap(),
+            "command command    "
+        );
+
+        assert_eq!(
+            replace_parameter("{{ /foo }}   command", &json!({ "foo": "bar" })).unwrap(),
+            "bar   command"
+        );
+
+        assert_eq!(
+            replace_parameter("   command  {{ /foo }}  ", &json!({ "foo": "bar" })).unwrap(),
+            "   command  bar  "
+        );
+
+        assert_eq!(
+            replace_parameter(
+                "{{ /foo }}   command{{/field1/foo}}",
+                &json!({ "foo": "bar", "field1": { "foo": "baz" } })
+            )
+            .unwrap(),
+            "bar   commandbaz"
+        );
+
+        assert_eq!(
+            replace_parameter("   command  {{ /foo }}  ", &json!({ "foo": "bar" })).unwrap(),
+            "   command  bar  "
+        );
+
+        assert_eq!(
+            replace_parameter(
+                "   {{ /field1/foo }}   command",
+                &json!({ "field1": { "foo": "bar" } })
+            )
+            .unwrap(),
+            "   bar   command"
+        );
+    }
 }