From 9bfb9dd2e8fa187a36c4ef98a491b9c2944bbd11 Mon Sep 17 00:00:00 2001
From: David Luevano Alvarado <david@luevano.xyz>
Date: Mon, 18 Apr 2022 22:39:11 -0600
Subject: add meaningful error messages when missing mandatory metadata

---
 README.md         |  2 +-
 src/pyssg/page.py | 20 +++++++++++++++-----
 2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/README.md b/README.md
index 722ada4..8a56246 100644
--- a/README.md
+++ b/README.md
@@ -21,7 +21,7 @@ Inspired (initially) by Roman Zolotarev's [`ssg5`](https://rgz.ee/bin/ssg5) and
 	- [x] Use [`configparser`](https://docs.python.org/3/library/configparser.html) instead of custom config handler.
 	- [ ] Migrate to YAML instead of INI, as it is way more flexible.
 - [x] Avoid the program to freak out when there are directories created in advance.
-- [ ] Provide more meaningful error messages when you are missing mandatory tags in your `.md` files.
+- [x] Provide more meaningful error messages when you are missing mandatory metadata in your `*.md` files.
 - [ ] More complex directory structure to support multiple subdomains and different types of pages.
 - [ ] Add option/change to using an SQL database instead of the custom solution.
 
diff --git a/src/pyssg/page.py b/src/pyssg/page.py
index dd3881c..82a0431 100644
--- a/src/pyssg/page.py
+++ b/src/pyssg/page.py
@@ -1,3 +1,4 @@
+import os
 import sys
 from datetime import datetime, timezone
 import logging
@@ -61,15 +62,24 @@ class Page:
         return self.ctimestamp < other.ctimestamp
 
 
+    def __get_mandatory_meta(self, meta: str) -> str:
+        try:
+            log.debug('parsing required metadata "%s"', meta)
+            return self.meta[meta][0]
+        except KeyError:
+            log.error('failed to parse mandatory metadata "%s" from file "%s"',
+                      meta, os.path.join(self.config.get('path', 'src'), self.name))
+            sys.exit(1)
+
+
     # parses meta from self.meta, for og, it prioritizes,
     # the actual og meta
     def parse_metadata(self):
         log.debug('parsing metadata for file "%s"', self.name)
-        log.debug('parsing required metadata')
-        self.title = self.meta['title'][0]
-        self.author = self.meta['author'][0]
-        self.summary = self.meta['summary'][0]
-        self.lang = self.meta['lang'][0]
+        self.title = self.__get_mandatory_meta('title')
+        self.author = self.__get_mandatory_meta('author')
+        self.summary = self.__get_mandatory_meta('summary')
+        self.lang = self.__get_mandatory_meta('lang')
 
         log.debug('parsing timestamp')
         self.cdatetime = datetime.fromtimestamp(self.ctimestamp,
-- 
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