jekyll-tools/add_redirects.py at main · cjmartin/jekyll-tools · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
import os
import yaml
import argparse
from datetime import datetime

def load_config(site_dir):
    """Load the _config.yml file from the specified site directory."""
    config_path = os.path.join(site_dir, "_config.yml")
    with open(config_path, "r", encoding="utf-8") as f:
        return yaml.safe_load(f)

def generate_permalink(format_string, metadata, file_name):
    """Generate the permalink based on the format string and metadata."""
    # Extract date from the file name (assuming YYYY-MM-DD-title.md format)
    if "date" not in metadata:
        date_str = file_name.split("-")[:3]  # Extract YYYY-MM-DD
        metadata["date"] = datetime.strptime("-".join(date_str), "%Y-%m-%d")

    # Replace placeholders in the format string
    permalink = format_string
    if ":title" in permalink:
        # Always use the title derived from the filename
        title_from_filename = os.path.splitext(file_name)[0].split("-", 3)[-1]
        metadata["title"] = title_from_filename  # Overwrite metadata title with filename title
        permalink = permalink.replace(":title", metadata["title"])
    if ":year" in permalink:
        permalink = permalink.replace(":year", str(metadata["date"].year))
    if ":month" in permalink:
        permalink = permalink.replace(":month", f"{metadata['date'].month:02d}")
    if ":day" in permalink:
        permalink = permalink.replace(":day", f"{metadata['date'].day:02d}")
    if ":categories" in permalink:
        categories = metadata.get("categories", "")
        permalink = permalink.replace(":categories", categories)

    # Ensure the permalink starts and ends with a slash
    if not permalink.startswith("/"):
        permalink = "/" + permalink
    if not permalink.endswith("/"):
        permalink += "/"
    return permalink

def update_redirects(site_dir):
    """Update all posts with redirect_from based on the current permalink format."""
    posts_dir = os.path.join(site_dir, "_posts")
    config = load_config(site_dir)
    permalink_format = config.get("permalink", "/:title/")  # Default permalink format

    for root, _, files in os.walk(posts_dir):
        for file in files:
            if file.endswith(".md") or file.endswith(".markdown"):
                file_path = os.path.join(root, file)
                with open(file_path, "r", encoding="utf-8") as f:
                    lines = f.readlines()

                # Check if the file has front matter
                if lines[0].strip() == "---":
                    # Extract front matter
                    end_index = lines[1:].index("---\n") + 1
                    front_matter_lines = lines[1:end_index]
                    content = lines[end_index + 1:]

                    # Parse front matter without altering its formatting
                    front_matter = yaml.safe_load("".join(front_matter_lines))

                    # Generate the current permalink
                    current_permalink = generate_permalink(permalink_format, front_matter, file)

                    # Add or update redirect_from in front matter
                    if "redirect_from" not in front_matter:
                        front_matter["redirect_from"] = []
                    if current_permalink not in front_matter["redirect_from"]:
                        front_matter["redirect_from"].append(current_permalink)

                    # Update the front matter lines with the new redirect_from value
                    redirect_from_yaml = yaml.dump(
                        {"redirect_from": front_matter["redirect_from"]},
                        default_flow_style=False
                    ).strip()
                    updated_front_matter_lines = []
                    redirect_from_added = False

                    for line in front_matter_lines:
                        if line.startswith("redirect_from:"):
                            # Replace the existing redirect_from line
                            updated_front_matter_lines.append(redirect_from_yaml + "\n")
                            redirect_from_added = True
                        else:
                            updated_front_matter_lines.append(line)

                    if not redirect_from_added:
                        # Add redirect_from at the end of the front matter
                        updated_front_matter_lines.append(redirect_from_yaml + "\n")

                    # Write the updated file, preserving original front matter formatting
                    with open(file_path, "w", encoding="utf-8") as f:
                        f.write("---\n")
                        f.writelines(updated_front_matter_lines)  # Write updated front matter lines
                        f.write("---\n")
                        f.writelines(content)

def main():
    parser = argparse.ArgumentParser(description="Add redirect_from front matter to Jekyll posts.")
    parser.add_argument("site_dir", help="Path to the Jekyll site directory")
    args = parser.parse_args()

    update_redirects(args.site_dir)

if __name__ == "__main__":
    main()