142 lines
6.9 KiB
Markdown
142 lines
6.9 KiB
Markdown
# Provider authoring: ResultTable & provider adapters ✅
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This short guide explains how to write providers that integrate with the *strict* ResultTable API: adapters must yield `ResultModel` instances and providers register via `SYS.result_table_adapters.register_provider` with a column specification and a `selection_fn`.
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---
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## Quick summary
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- Providers register a *provider adapter* (callable that yields `ResultModel`).
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- Providers must also provide `columns` (static list or factory) and a `selection_fn` that returns CLI args for a selected row.
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- For simple HTML table/list scraping, prefer `TableProviderMixin` from `SYS.provider_helpers` to fetch and extract rows using `SYS.html_table.extract_records`.
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## Runtime dependency policy
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- Treat required runtime dependencies (e.g., **Playwright**) as mandatory: import them unconditionally and let missing dependencies fail fast at import time. Avoid adding per-call try/except import guards for required modules—these silently hide configuration errors and add bloat.
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- Use guarded imports only for truly optional dependencies (e.g., `pandas` for enhanced table parsing) and provide meaningful fallbacks or helpful error messages in those cases.
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- Keep provider code minimal and explicit: fail early and document required runtime dependencies in README/installation notes.
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---
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## Minimal provider template (copy/paste)
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```py
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# Provider/my_provider.py
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from typing import Any, Dict, Iterable, List
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from SYS.result_table_api import ResultModel, ColumnSpec, title_column, metadata_column
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from SYS.result_table_adapters import register_provider
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# Example adapter: convert provider-specific items into ResultModel instances
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SAMPLE_ITEMS = [
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{"name": "Example File.pdf", "path": "https://example.com/x.pdf", "ext": "pdf", "size": 1024, "source": "myprovider"},
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]
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def adapter(items: Iterable[Dict[str, Any]]) -> Iterable[ResultModel]:
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for it in items:
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title = it.get("name") or it.get("title") or str(it.get("path") or "")
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yield ResultModel(
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title=str(title),
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path=str(it.get("path")) if it.get("path") else None,
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ext=str(it.get("ext")) if it.get("ext") else None,
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size_bytes=int(it.get("size")) if it.get("size") is not None else None,
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metadata=dict(it),
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source=str(it.get("source")) if it.get("source") else "myprovider",
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)
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# Optional: build columns dynamically from sample rows
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def columns_factory(rows: List[ResultModel]) -> List[ColumnSpec]:
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cols = [title_column()]
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# add extra columns if metadata keys exist
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if any((r.metadata or {}).get("size") for r in rows):
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cols.append(ColumnSpec("size", "Size", lambda r: r.size_bytes or ""))
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return cols
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# Selection args for `@N` expansion or `select` cmdlet
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def selection_fn(row: ResultModel) -> List[str]:
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# prefer -path when available
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if row.path:
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return ["-path", row.path]
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return ["-title", row.title or ""]
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# Register provider (done at import time)
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register_provider("myprovider", adapter, columns=columns_factory, selection_fn=selection_fn)
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```
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---
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## Table scraping: using TableProviderMixin (HTML tables / list-results)
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If your provider scrapes HTML tables or list-like results (common on web search pages), use `TableProviderMixin`:
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```py
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from ProviderCore.base import Provider
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from SYS.provider_helpers import TableProviderMixin
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class MyTableProvider(TableProviderMixin, Provider):
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URL = ("https://example.org/search",)
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def validate(self) -> bool:
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return True
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def search(self, query: str, limit: int = 50, **kwargs):
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url = f"{self.URL[0]}?q={quote_plus(query)}"
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return self.search_table_from_url(url, limit=limit)
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```
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`TableProviderMixin.search_table_from_url` returns `ProviderCore.base.SearchResult` entries. If you want to integrate this provider with the strict `ResultTable` registry, add a small adapter that converts `SearchResult` -> `ResultModel` and register it using `register_provider` (see `Provider/vimm.py` for a real example).
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---
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## Columns & selection
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- `columns` may be a static `List[ColumnSpec]` or a factory `def cols(rows: List[ResultModel]) -> List[ColumnSpec]` that inspects sample rows.
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- `selection_fn` must accept a `ResultModel` and return a `List[str]` representing CLI args (e.g., `['-path', row.path]`). These args are used by `select` and `@N` expansion.
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**Tip:** for providers that produce downloadable file rows prefer returning explicit URL args (e.g., `['-url', row.path]`) so the selected URL is clearly identified by downstream downloaders and to avoid ambiguous parsing when provider hints (like `-provider`) are present.
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- Ensure your `ResultModel.source` is set (either in the model or rely on the provider name set by `serialize_row`).
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---
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## Optional: pandas path for `<table>` extraction
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`SYS.html_table.extract_records` prefers a pure-lxml path but will use `pandas.read_html` if pandas is installed and the helper detects it works for the input table. This is optional and **not required** to author a provider — document in your provider whether it requires `pandas` and add an informative error/log message when it is missing.
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---
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## Testing & examples
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- Write `tests/test_provider_<name>.py` that imports your provider and verifies `provider.build_table(...)` produces a `ResultTable` (has `.rows` and `.columns`) and that `serialize_rows()` yields dicts with `_selection_args`, `_selection_action` when applicable, and `source`.
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- When you need to guarantee a specific CLI stage sequence (e.g., `download-file -url <path> -provider <name>`), call `table.set_row_selection_action(row_index, tokens)` so the serialized payload emits `_selection_action` and the CLI can run the row exactly as intended.
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- For table providers you can test `search_table_from_url` using a local HTML fixture or by mocking `HTTPClient` to return a small sample page.
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- If you rely on pandas, add a test that monkeypatches `sys.modules['pandas']` to a simple shim to validate the pandas path.
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**Example test skeleton**
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```py
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from SYS.result_table_adapters import get_provider
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from Provider import example_provider
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def test_example_provider_registration():
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provider = get_provider("example")
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rows = list(provider.adapter(example_provider.SAMPLE_ITEMS))
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assert rows and rows[0].title
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cols = provider.get_columns(rows)
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assert any(c.name == "title" for c in cols)
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table = provider.build_table(example_provider.SAMPLE_ITEMS)
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assert table.provider == "example" and table.rows
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```
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---
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## References & examples
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- Read `Provider/example_provider.py` for a compact example of a strict adapter and dynamic columns.
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- Read `Provider/vimm.py` for a table-provider that uses `TableProviderMixin` and converts `SearchResult` → `ResultModel` for registration.
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- See `docs/provider_guide.md` for a broader provider development checklist.
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---
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If you want, I can also add a small `Provider/myprovider_template.py` file and unit tests for it — say the word and I'll add them and wire up tests. 🎯
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