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FastAPI-first import/export toolkit with composable workflows and pluggable backends.
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Basierend auf der SOC-Berufsklassifikation
| name | fastapi-import-export |
| description | FastAPI-first import/export toolkit with composable workflows and pluggable backends. |
This skill helps you build and operate import/export workflows for FastAPI. It now includes stable overwrite semantics, unified error codes, template contracts, observability events, and performance regression gating.
本技能用于构建并运维 FastAPI 导入导出流程。 当前能力已覆盖稳定覆盖策略、统一错误码、模板契约、可观测事件与性能门禁。
export_* / import_* top-level functions.ExportOptions / ImportOptions (explicit configuration).reject / upsert / replace.schema_error / type_error / db_conflict.fastapi_import_export.advanced.fastapi_import_export.contrib.* (requires [sqlalchemy] / [sqlmodel] / [tortoise]).event_hook) with lifecycle events.get_book_template_contract).Easy Layer (Top-level)
export_csv(source, *, resource=None, params=None, options=None) -> ExportPayloadexport_xlsx(source, *, resource=None, params=None, options=None) -> ExportPayloadimport_csv(file, *, resource, validate_fn, persist_fn, options=None) -> ImportResultimport_xlsx(file, *, resource, validate_fn, persist_fn, options=None) -> ImportResultOptions Layer
ExportOptions
filename: str | Nonemedia_type: str | Noneinclude_bom: bool (default: False)line_ending: str (default: "\r\n")chunk_size: int (default: 64 * 1024)columns: list[str] | NoneImportOptions
db: Any | Noneallow_overwrite: bool (default: False)overwrite_mode: OverwriteMode | str | Noneunique_fields: list[str] | Nonedb_checks: list[DbCheckSpec] | Noneallowed_extensions: Iterable[str] | Noneallowed_mime_types: Iterable[str] | NoneCore Types
Resource
field_aliases: dict[str, str]field_mapping() -> dict[str, str]export_aliases: dict[str, str]export_mapping() -> dict[str, str]field_codecs: dict[str, Codec]model: Any | Noneexclude_fields: list[str]Importer
import_data(*, file, resource, allow_overwrite=False) -> ImportResultparse(*, file, resource) -> TTablevalidate(*, data, resource, allow_overwrite) -> tuple[TTable, list[TError]]transform(*, data, resource) -> TTablepersist(*, data, resource, allow_overwrite) -> intExporter
query(*, resource, params=None) -> TTableserialize(*, data, fmt) -> bytesrender(*, data, fmt) -> ByteStreamstream(*, resource, fmt, filename, media_type, params=None) -> ExportPayloadImportExportService
__init__(..., redis_client=None, event_hook=None, config=None, base_dir=None, max_upload_mb=20, lock_ttl_seconds=300)upload_parse_validate(*, file, column_aliases, validate_fn, allow_overwrite=False, overwrite_mode=None, unique_fields=None, db_checks=None, allowed_extensions=None, allowed_mime_types=None) -> ImportValidateResponsepreview(*, import_id, checksum, page, page_size, kind) -> ImportPreviewResponsecommit(*, body, persist_fn, lock_namespace="import") -> ImportCommitResponseConfig and Facades
resolve_config(...) -> ImportExportConfigparse_tabular_file(file_path, *, filename)normalize_columns(df, column_mapping)dataframe_to_preview_rows(df)collect_infile_duplicates(df, unique_fields)run_db_checks(*, db, df, specs, allow_overwrite=False)Errors
ImportExportError with message, status_code, details, error_codeParseError / ValidationError / PersistError / ExportErrorImportErrorItem includes row_number, field, type, messageUnified validation error code contract
schema_error: Contract/required/enum/in-file duplicate errors.type_error: Parse/coercion/type conversion errors.db_conflict: Database uniqueness/conflict errors.ImportExportError common error_code values
missing_dependency: Backend/adapter dependency is missing (bundled package removed or optional adapter not installed).unsupported_media_type: File extension or MIME type is not allowed.import_export_error: Default fallback code for generic errors.Easy Export
source can be Iterable[Mapping], polars.DataFrame, or query_fn.source is callable, it is treated as query_fn.options.columns > Resource field order > inferred from rows.Resource.export_mapping() is applied.media_type derived from format; CSV uses \\r\\n and no BOM.Easy Import
import_csv/import_xlsx runs upload -> parse -> validate -> commit.validate_fn and persist_fn only.overwrite_mode > allow_overwrite.ImportResult(status=VALIDATED, errors=...).ImportResult(status=COMMITTED, imported_rows=...).Importer.import_data
file, resourceallow_overwriteImportResult with status, imported_rows, errorsExporter.stream
resource, fmt, filename, media_typeparamsExportPayload with filename, media_type, streamImportExportService.upload_parse_validate
file, column_aliases, validate_fnallow_overwrite, overwrite_mode, unique_fields, db_checks, allowed_extensions, allowed_mime_typesImportValidateResponse with import_id, checksum, total_rows, valid_rows, error_rows, errorsmax_upload_mbImportExportService.preview
import_id (UUID), checksum, page, page_size, kindkind is all or validImportPreviewResponse with rows (list of ImportPreviewRow)ImportExportService.commit
body, persist_fnlock_namespaceImportCommitResponse with imported_rows, status, created_atImportExportService observability
event_hook(event: dict) -> None | awaitableupload_parse_validate.started/completed/failedpreview.started/completed/failedcommit.started/completed/failedImportErrorItem
{
"row_number": 12,
"field": "email",
"type": "schema_error",
"message": "Duplicate value for field email: a@b.com"
}
ImportValidateResponse (partial)
{
"import_id": "uuid",
"checksum": "sha256",
"total_rows": 100,
"valid_rows": 95,
"error_rows": 5,
"errors": [
{"row_number": 12, "field": "email", "message": "Duplicate value for field email: a@b.com"}
]
}
resolve_config(allowed_extensions, allowed_mime_types) or per-call override.openpyxl in easy layer.field_codecs.Resource.model is set and no fields are declared, fields are inferred from the ORM model.validate_fn/persist_fn and formats values during export.ImportOptions.overwrite_mode.field_codecs / __import_export_codecs__.Example (Enum/Date/Decimal)
from enum import Enum
from fastapi_import_export import Resource
from fastapi_import_export.codecs import DateCodec, DecimalCodec, EnumCodec
class Status(Enum):
DRAFT = "draft"
PUBLISHED = "published"
class BookResource(Resource):
field_codecs = {
"status": EnumCodec(Status),
"published_at": DateCodec(),
"price": DecimalCodec(),
}
Rules when Resource.model is set and no fields are declared:
model.__table__.columns (SQLAlchemy/SQLModel) or model._meta (Tortoise)id), created_at, updated_at, soft-delete flagsexclude_fields = ["password"]field_aliases overrides auto mapping (merge: auto mapping then update with field_aliases)class BookResource(Resource):
model = Book
exclude_fields = ["password"]
field_aliases = {"Author": "author"}
0) Easy Export (Top-level)
from fastapi import StreamingResponse
from fastapi_import_export import export_csv, Resource
class UserResource(Resource):
id: int | None
username: str
async def query_fn(*, resource, params=None):
return [{"id": 1, "username": "alice"}]
payload = await export_csv(query_fn, resource=UserResource)
return StreamingResponse(payload.stream, media_type=payload.media_type)
0.1) Easy Import (Top-level)
from fastapi_import_export import import_csv
async def validate_fn(db, df, *, allow_overwrite: bool = False):
return df, []
async def persist_fn(db, valid_df, *, allow_overwrite: bool = False) -> int:
return int(valid_df.height)
result = await import_csv(file, resource=UserResource, validate_fn=validate_fn, persist_fn=persist_fn)
0.2) Easy Import with overwrite mode
from fastapi_import_export import import_csv
from fastapi_import_export.options import ImportOptions
result = await import_csv(
file,
resource=UserResource,
validate_fn=validate_fn,
persist_fn=persist_fn,
options=ImportOptions(overwrite_mode="upsert"),
)
1) Define Resource and Importer
from fastapi_import_export.advanced import Importer, Resource
class UserResource(Resource):
id: int | None
username: str
email: str
field_aliases = {"Username": "username", "Email": "email"}
importer = Importer(
parser=parse_fn,
validator=validate_fn,
transformer=transform_fn,
persister=persist_fn,
)
2) Streaming export
payload = await exporter.stream(
resource=UserResource,
fmt="csv",
filename="users.csv",
media_type="text/csv",
)
2.1) Exporter module usage
import csv
import io
from collections.abc import AsyncIterator
from fastapi_import_export.advanced import Exporter, Resource
class UserResource(Resource):
id: int | None
username: str
async def query_fn(*, resource: type[Resource], params: dict | None = None):
return [
{"id": 1, "username": "alice"},
{"id": 2, "username": "bob"},
]
async def serialize_fn(*, data: list[dict], fmt: str) -> bytes:
buf = io.StringIO()
writer = csv.DictWriter(buf, fieldnames=["id", "username"])
writer.writeheader()
writer.writerows(data)
return buf.getvalue().encode("utf-8-sig")
async def render_fn(*, data: bytes, fmt: str) -> AsyncIterator[bytes]:
async def _stream() -> AsyncIterator[bytes]:
yield data
return _stream()
exporter = Exporter(query_fn=query_fn, serialize_fn=serialize_fn, render_fn=render_fn)
payload = await exporter.stream(
resource=UserResource,
fmt="csv",
filename="users.csv",
media_type="text/csv",
)
3) Service workflow
from fastapi_import_export.advanced import ImportExportService
svc = ImportExportService(db=object())
resp = await svc.upload_parse_validate(
file=file,
column_aliases=UserResource.field_mapping(),
validate_fn=service_validate_fn,
)
commit = await svc.commit(body=commit_body, persist_fn=service_persist_fn)
4) Upload allowlist configuration
from fastapi_import_export.config import resolve_config
cfg = resolve_config(allowed_extensions=[".csv"], allowed_mime_types=["text/csv"])
svc = ImportExportService(db=object(), config=cfg)
fastapi_import_export.advanced.Importer for custom parse/validate/transform/persist.fastapi_import_export.advanced.Exporter for custom query/serialize/render.fastapi_import_export.advanced.ImportExportService for upload/preview/commit workflows.parse, validation, db_validation, storage to plug backends.get_book_template_contract() returns a built-in book import contract.BOOK_TEMPLATE_COLUMNSBOOK_STATUS_ENUMUse these presets to keep header/value contracts stable across front-end, ops, and backend teams.
Benchmark script:
benchmarks/benchmark_import_service.pyKey options:
--kind csv|xlsx--rows <int>--seed <int>--warmup <int>--rounds <int>--export-json <path>--baseline-json <path>--regression-threshold <float>--fail-on-regressionCI workflow:
.github/workflows/performance-gate.yml.perf/baseline.json as baseline.bytesadvanced.Exporter.serialize or your own wrapper in the easy layer.AsyncIterator[bytes].
parse -> validate -> transform -> persist
validate returns (valid_data, errors). If errors is non-empty, skip transform/persist.allow_overwrite is passed through to validation and persistence.query -> serialize -> render
query returns table-like data.serialize returns bytes.render returns an async byte stream.parse and validation default to Polars backends (bundled by default).storage defaults to filesystem storage (bundled by default).\\r\\n line endings.options.columns > Resource field order > inferred.export_aliases > invertible field_aliases > identity.