json.py

__package__ = 'archivebox.index'

import os
import sys
import json as pyjson

from datetime import datetime
from typing import List, Optional, Iterator, Any

from .schema import Link, ArchiveResult
from ..system import atomic_write
from ..util import enforce_types
from ..config import (
    VERSION,
    OUTPUT_DIR,
    FOOTER_INFO,
    GIT_SHA,
    DEPENDENCIES,
    JSON_INDEX_FILENAME,
    ARCHIVE_DIR_NAME,
)


MAIN_INDEX_HEADER = {
    'info': 'This is an index of site data archived by ArchiveBox: The self-hosted web archive.',
    'schema': 'archivebox.index.json',
    'copyright_info': FOOTER_INFO,
    'meta': {
        'project': 'ArchiveBox',
        'version': VERSION,
        'git_sha': GIT_SHA,
        'website': 'https://ArchiveBox.io',
        'docs': 'https://github.com/pirate/ArchiveBox/wiki',
        'source': 'https://github.com/pirate/ArchiveBox',
        'issues': 'https://github.com/pirate/ArchiveBox/issues',
        'dependencies': DEPENDENCIES,
    },
}


### Main Links Index

@enforce_types
def parse_json_main_index(out_dir: str=OUTPUT_DIR) -> Iterator[Link]:
    """parse an archive index json file and return the list of links"""

    index_path = os.path.join(out_dir, JSON_INDEX_FILENAME)
    if os.path.exists(index_path):
        with open(index_path, 'r', encoding='utf-8') as f:
            links = pyjson.load(f)['links']
            for link_json in links:
                yield Link.from_json(link_json)

    return ()

@enforce_types
def write_json_main_index(links: List[Link], out_dir: str=OUTPUT_DIR) -> None:
    """write the json link index to a given path"""

    assert isinstance(links, List), 'Links must be a list, not a generator.'
    assert not links or isinstance(links[0].history, dict)
    assert not links or isinstance(links[0].sources, list)

    if links and links[0].history.get('title'):
        assert isinstance(links[0].history['title'][0], ArchiveResult)

    if links and links[0].sources:
        assert isinstance(links[0].sources[0], str)

    main_index_json = {
        **MAIN_INDEX_HEADER,
        'num_links': len(links),
        'updated': datetime.now(),
        'last_run_cmd': sys.argv,
        'links': links,
    }
    atomic_write(main_index_json, os.path.join(out_dir, JSON_INDEX_FILENAME))


### Link Details Index

@enforce_types
def write_json_link_details(link: Link, out_dir: Optional[str]=None) -> None:
    """write a json file with some info about the link"""
    
    out_dir = out_dir or link.link_dir
    path = os.path.join(out_dir, JSON_INDEX_FILENAME)

    atomic_write(link._asdict(extended=True), path)


@enforce_types
def parse_json_link_details(out_dir: str) -> Optional[Link]:
    """load the json link index from a given directory"""
    existing_index = os.path.join(out_dir, JSON_INDEX_FILENAME)
    if os.path.exists(existing_index):
        with open(existing_index, 'r', encoding='utf-8') as f:
            try:
                link_json = pyjson.load(f)
                return Link.from_json(link_json)
            except pyjson.JSONDecodeError:
                pass
    return None


@enforce_types
def parse_json_links_details(out_dir: str) -> Iterator[Link]:
    """read through all the archive data folders and return the parsed links"""

    for entry in os.scandir(os.path.join(out_dir, ARCHIVE_DIR_NAME)):
        if entry.is_dir(follow_symlinks=True):
            if os.path.exists(os.path.join(entry.path, 'index.json')):
                link = parse_json_link_details(entry.path)
                if link:
                    yield link



### Helpers

class ExtendedEncoder(pyjson.JSONEncoder):
    """
    Extended json serializer that supports serializing several model
    fields and objects
    """

    def default(self, obj):
        cls_name = obj.__class__.__name__

        if hasattr(obj, '_asdict'):
            return obj._asdict()

        elif isinstance(obj, bytes):
            return obj.decode()

        elif isinstance(obj, datetime):
            return obj.isoformat()

        elif isinstance(obj, Exception):
            return '{}: {}'.format(obj.__class__.__name__, obj)

        elif cls_name in ('dict_items', 'dict_keys', 'dict_values'):
            return tuple(obj)

        return pyjson.JSONEncoder.default(self, obj)


@enforce_types
def to_json(obj: Any, indent: Optional[int]=4, sort_keys: bool=True, cls=ExtendedEncoder) -> str:
    return pyjson.dumps(obj, indent=indent, sort_keys=sort_keys, cls=ExtendedEncoder)