From 84f99cc49c9dc2ca9ebcf333061af3bf6fa129e3 Mon Sep 17 00:00:00 2001
From: Konstantin Pogorelov <or@pluseq.com>
Date: Wed, 8 Aug 2018 11:23:27 +0200
Subject: [PATCH] add urlValueParser option, update docs accordingly

---
 README.md            | 18 +++++++++++++++++-
 advanced-example.js  |  5 +++++
 src/normalizePath.js |  6 ++++--
 3 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/README.md b/README.md
index 5035914..cfca740 100644
--- a/README.md
+++ b/README.md
@@ -52,6 +52,9 @@ Which labels to include in `http_request_duration_seconds` metric:
 
 Extra transformation callbacks:
 
+* **urlValueParser**: options passed when instantiating [url-value-parser](https://github.com/disjunction/url-value-parser).
+  This is the easiest way to customize which parts of the URL should be replaced with "#val".
+  See the [docs](https://github.com/disjunction/url-value-parser) of url-value-parser module for details.
 * **normalizePath**: `function(req)` generates path values from express `req` (see details below)
 * **formatStatusCode**: `function(res)` producing final status code from express `res` object, e.g. you can combine `200`, `201` and `204` to just `2xx`.
 * **transformLabels**: `function(labels, req, res)` transforms the **labels** object, e.g. setting dynamic values to **customLabels**
@@ -150,7 +153,9 @@ app.listen(3000);
 
 ## using with kraken.js
 
-Here is meddleware config sample, which can be used in a standard **kraken.js** application:
+Here is meddleware config sample, which can be used in a standard **kraken.js** application.
+In this case the stats for URI paths and HTTP methods are collected separately,
+while replacing all HEX values starting from 5 characters and all emails in the path as #val.
 
 ```json
 {
@@ -163,11 +168,18 @@ Here is meddleware config sample, which can be used in a standard **kraken.js**
         "arguments": [
           {
             "includeMethod": true,
+            "includePath": true,
             "buckets": [0.1, 1, 5],
             "promClient": {
               "collectDefaultMetrics": {
                 "timeout": 2000
               }
+            },
+            "urlValueParser": {
+              "minHexLength": 5,
+              "extraMasks": [
+                "^[^@]+@[^@]+\\.[^@]+$"
+              ]
             }
           }
         ]
@@ -179,6 +191,10 @@ Here is meddleware config sample, which can be used in a standard **kraken.js**
 
 ## Changelog
 
+* **4.0.0**
+    * added option **urlValueParser**
+    * upgrade **prom-client** to ~11.1.1
+
  * **3.3.0**
     * added option **promClient** to be able to call collectDefaultMetrics
     * upgrade **prom-client** to ~10.2.2 (switch to semver "approximately")
diff --git a/advanced-example.js b/advanced-example.js
index ae49fb5..9ce4ba9 100644
--- a/advanced-example.js
+++ b/advanced-example.js
@@ -17,6 +17,10 @@ const bundle = promBundle({
     }
   },
   urlValueParser: {
+    minHexLength: 5,
+    extraMasks: [
+      "^[^@]+@[^@]+\\.[^@]+$"
+    ]
   }
 });
 
@@ -42,6 +46,7 @@ app.listen(3000, () => console.info(  // eslint-disable-line
   'listening on 3000\n'
   + 'test in shell console\n\n'
   + 'curl localhost:3000/foo/1234\n'
+  + 'curl localhost:3000/foo/john%40example.com\n'
   + 'curl -X DELETE localhost:3000/foo/5432\n'
   + 'curl localhost:3000/bar\n'
   + 'curl localhost:3000/metrics\n'
diff --git a/src/normalizePath.js b/src/normalizePath.js
index 677cc8d..d40fd18 100644
--- a/src/normalizePath.js
+++ b/src/normalizePath.js
@@ -2,16 +2,18 @@
 
 const UrlValueParser = require('url-value-parser');
 const url = require('url');
+
+// ATTENTION! urlValueParser is a singleton!
 let urlValueParser;
 
-module.exports = function(req) {
+module.exports = function(req, opts) {
   // originalUrl is taken, because url and path can be changed
   // by middlewares such as 'router'. Note: this function is called onFinish
   /// i.e. always in the tail of the middleware chain
   const path = url.parse(req.originalUrl || req.url).pathname;
 
   if (!urlValueParser) {
-    urlValueParser = new UrlValueParser();
+    urlValueParser = new UrlValueParser(opts && opts.urlValueParser);
   }
   return urlValueParser.replacePathValues(path);
 };