OpenAPI

Schema building, security schemes, documentation UIs, route iteration

Source files:

core/sillo/openapi/config.py, OpenAPIConfig

core/sillo/openapi/models.py: Pydantic OpenAPI 3.0 models (OpenAPI, Info, PathItem, Operation, Schema, Components, etc.)

core/sillo/openapi/_builder.py, APIDocumentation

core/sillo/openapi/ui.py: DocsUI, Atlas, Swagger, ReDoc, Scalar, default_docs

core/sillo/openapi/utils.py, get_openapi (route flattening utility)

core/sillo/openapi/__init__.py. Public re-exports

14.1 Architecture Overview

Sillo’s OpenAPI system generates a complete OpenAPI 3.0 specification from route declarations and validated parameter models. The document is built once after all routes are registered and served as a static JSON file. Documentation UIs (Atlas, Swagger, ReDoc, Scalar) render it client-side.

flowchart LR
    subgraph Registration["Route Registration"]
        R["Route objects<br/>(handlers + markers + models)"]
    end

    subgraph Build["Document Build (once)"]
        AD["APIDocumentation.get_openapi()"]
        AD --> CR["_collect_routes_with_paths()"]
        CR --> AR["_add_route_to_openapi_spec()"]
        AR --> PR["_build_parameters_spec()"]
        AR --> RB["_build_request_body_spec()"]
        AR --> RS["_build_responses_spec()"]
        AR --> SEC["_route_security()"]
        PR & RB & RS --> OD["OpenAPI spec dict"]
    end

    subgraph Serve["Serving"]
        OD --> JSON["/openapi.json"]
        JSON --> Atlas["Atlas /docs"]
        JSON --> Swagger["Swagger /docs"]
        JSON --> ReDoc["ReDoc /redoc"]
        JSON --> Scalar["Scalar /reference"]
    end

    R --> AD

14.2 `OpenAPIConfig`

# core/sillo/openapi/config.py:21-163
class OpenAPIConfig:
    def __init__(
        self,
        title: str = "API Documentation",
        version: str = "1.0.0",
        description: str = "",
        servers: list[Server] | None = [],
        contact: Contact | None = None,
        license: License | None = None,
        termsOfService: str | None = None,
        openapi_version: str = "3.0.0",
    ):

OpenAPIConfig holds the OpenAPI document and provides methods to modify its components section. It is the single source of truth for the spec.

14.2.1 Constructor Fields

Field	Type	Default	Description
`title`	`str`	`"API Documentation"`	API title in the `info` block.
`version`	`str`	`"1.0.0"`	API version.
`description`	`str`	`""`	API description.
`servers`	`list[Server]`	`[]`	Server entries.
`contact`	`Contact`	`None`	Contact info.
`license`	`License`	`None`	License info.
`termsOfService`	`str`	`None`	Terms of service URL.
`openapi_version`	`str`	`"3.0.0"`	OpenAPI spec version.

14.2.2 Internal State

The config creates an OpenAPI Pydantic model in __init__:

# config.py:36-49
self.openapi_spec = OpenAPI(
    openapi=openapi_version,
    info=Info(
        title=title, version=version, description=description,
        contact=contact, license=license, termsOfService=termsOfService,
    ),
    paths={},
    servers=servers,
    components=Components(),
)

14.2.3 Component Registration Methods

`add_security_scheme(name, scheme)`

# config.py:69-77
def add_security_scheme(self, name: str, scheme: SecurityScheme):
    if not self.openapi_spec.components:
        self.openapi_spec.components = Components()
    if not self.openapi_spec.components.securitySchemes:
        self.openapi_spec.components.securitySchemes = {}
    self.openapi_spec.components.securitySchemes[name] = scheme

Registers a security scheme (API key, HTTP bearer, OAuth2, OpenID Connect).

`add_schema(name, schema)`

# config.py:79-92
def add_schema(self, name: str, schema: type[BaseModel] | Schema):
    if isinstance(schema, type) and issubclass(schema, BaseModel):
        self.openapi_spec.components.schemas[name] = Schema(**schema.model_json_schema())
    else:
        self.openapi_spec.components.schemas[name] = schema

Accepts either a Pydantic BaseModel subclass (auto-converted via model_json_schema()) or a raw Schema object.

`add_parameter(name, parameter)`

# config.py:94-102
def add_parameter(self, name: str, parameter: Parameter):
    ...
    self.openapi_spec.components.parameters[name] = parameter

Registers a reusable parameter component.

`add_response(name, response)`

# config.py:104-112
def add_response(self, name: str, response: OpenAPIResponse):
    ...
    self.openapi_spec.components.responses[name] = response

Registers a reusable response component.

`add_example(name, example)`

# config.py:114-122
def add_example(self, name: str, example: Example):
    ...
    self.openapi_spec.components.examples[name] = example

Registers an example component.

`add_tag(tag)`

# config.py:124-132
def add_tag(self, tag: Tag):
    if not self.openapi_spec.tags:
        self.openapi_spec.tags = []
    existing_tags = [t.name for t in self.openapi_spec.tags]
    if tag.name not in existing_tags:
        self.openapi_spec.tags.append(tag)

Adds a tag, deduplicating by name.

14.2.4 Additional Methods

Method	Description
`add_server(server)`	Add a server entry.
`set_external_docs(docs)`	Set external documentation link.
`set_global_security(sec)`	Set global security requirements.
`get_schema_ref(name)`	Returns `#/components/schemas/{name}`.
`get_parameter_ref(name)`	Returns `#/components/parameters/{name}`.
`get_response_ref(name)`	Returns `#/components/responses/{name}`.
`get_example_ref(name)`	Returns `#/components/examples/{name}`.

14.2.5 Security Schemes Property

# config.py:51-67
@property
def security_schemes(self) -> dict[str, SecurityScheme | Reference]:
    components = self.openapi_spec.components
    if components is None or not components.securitySchemes:
        return {}
    return components.securitySchemes

Reads directly from the document. This used to be a separate dict that was never written to, causing the application to report no security schemes.

14.3 Pydantic OpenAPI 3.0 Models

All OpenAPI structures are modeled as Pydantic BaseModel subclasses in core/sillo/openapi/models.py (494 lines). They provide validation, JSON serialization, and $ref support.

14.3.1 Document Root

# models.py:478-489
class OpenAPI(BaseModel):
    openapi: str
    info: Info
    paths: Annotated[dict[str, PathItem | Extension], Field(default_factory=dict)]
    servers: list[Server] | None = None
    components: Components = Components()
    security: list[dict[str, list[str]]] | None = None
    tags: list[Tag] | None = None
    externalDocs: ExternalDocumentation | None = None

14.3.2 Info Block

# models.py:44-54
class Info(BaseModel):
    title: str
    version: str
    description: str | None = None
    termsOfService: str | None = None
    contact: Contact | None = None
    license: License | None = None
    model_config = ConfigDict(extra="allow")

extra="allow" permits vendor extensions (x-* fields).

14.3.3 Path and Operation

# models.py:339-356
class PathItem(BaseModel):
    ref: Annotated[str | None, Field(alias="$ref")] = None
    summary: str | None = None
    description: str | None = None
    get: Operation | None = None
    put: Operation | None = None
    post: Operation | None = None
    delete: Operation | None = None
    options: Operation | None = None
    head: Operation | None = None
    patch: Operation | None = None
    trace: Operation | None = None
    servers: list[Server] | None = None
    parameters: list[Parameter | Reference] | None = None
    model_config = ConfigDict(extra="allow")

# models.py:316-333
class Operation(BaseModel):
    responses: dict[str, Response | Reference]
    tags: list[str] | None = None
    summary: str | None = None
    description: str | None = None
    externalDocs: ExternalDocumentation | None = None
    operationId: str | None = None
    parameters: list[ConcreteParameter | Reference] | None = None
    requestBody: RequestBody | Reference | None = None
    callbacks: dict[str, dict[str, PathItem] | Reference] | None = None
    deprecated: bool | None = None
    security: list[dict[str, list[str]]] | None = None
    servers: list[Server] | None = None
    model_config = ConfigDict(extra="allow")

14.3.4 Schema

# models.py:106-171
class Schema(BaseModel):
    ref: Annotated[str | None, Field(alias="$ref")] = None
    title: str | None = None
    multipleOf: float | None = None
    maximum: float | None = None
    exclusiveMaximum: float | None = None
    minimum: float | None = None
    exclusiveMinimum: float | None = None
    maxLength: Annotated[int | None, Field(ge=0)] = None
    minLength: Annotated[int | None, Field(ge=0)] = None
    pattern: str | None = None
    # ... (full JSON Schema vocabulary)
    type: str | None = None
    allOf: list[Schema] | None = None
    oneOf: list[Schema] | None = None
    anyOf: list[Schema] | None = None
    properties: dict[str, Schema] | None = None
    # ...

The validate_type field validator handles composition keywords. When anyOf/oneOf/allOf are present, type defaults to None instead of "object":

# models.py:155-171
@field_validator("type", mode="before")
@classmethod
def validate_type(cls, v, info):
    if v is not None:
        return v
    data = info.data if hasattr(info, "data") else {}
    has_composition = any(
        data.get(key) is not None for key in ["anyOf", "oneOf", "allOf"]
    )
    if not has_composition:
        return "object"
    return None

14.3.5 Parameter Models

# models.py:219-270
class ConcreteParameter(ParameterBase):
    name: str
    in_: ParameterLocations = Field(alias="in")

class Header(ConcreteParameter):
    in_: Literal["header"] = Field(default="header", serialization_alias="in")
    style: HeaderParamStyles = "simple"
    explode: bool = False
    spec: ... = Schema(type="string")

class Query(ConcreteParameter):
    in_: Literal["query"] = Field(default="query", serialization_alias="in")
    style: QueryParamStyles = "form"
    explode: bool = True
    spec: ... = Schema(type="string")

class Path(ConcreteParameter):
    in_: Literal["path"] = Field(default="path", alias="in")
    style: PathParamStyles = "simple"
    explode: bool = False
    required: Literal[True] = True

class Cookie(ConcreteParameter):
    in_: Literal["cookie"] = "cookie"
    style: CookieParamStyles = "form"
    explode: bool = True

Parameter = Union[Query, Header, Cookie, Path]

Each parameter type has appropriate defaults for its location (style, explode, required).

14.3.6 Security Scheme Models

# models.py:362-453
SecurityScheme = Union[APIKey, HTTPBase, OAuth2, OpenIdConnect, HTTPBearer]

Model	Type	Key Fields
`APIKey`	`"apiKey"`	`name`, `in_` (query/header/cookie)
`HTTPBase`	`"http"`	`scheme`
`HTTPBearer`	`"http"`	`scheme="bearer"`, `bearerFormat`
`OAuth2`	`"oauth2"`	`flows` (implicit/password/clientCredentials/authorizationCode)
`OpenIdConnect`	`"openIdConnect"`	`openIdConnectUrl`

14.3.7 Components

# models.py:456-467
class Components(BaseModel):
    schemas: dict[str, Schema | Reference] | None = None
    responses: dict[str, Response | Reference] | None = None
    parameters: dict[str, Parameter | Reference] | None = None
    examples: Examples | None = None
    requestBodies: dict[str, RequestBody | Reference] | None = None
    headers: dict[str, Header | Reference] | None = None
    securitySchemes: dict[str, SecurityScheme | Reference] | None = None
    links: dict[str, Link | Reference] | None = None
    callbacks: dict[str, dict[str, PathItem] | Reference] | None = None

14.3.8 Model Rebuilds

# models.py:492-494
Schema.model_rebuild()
Operation.model_rebuild()
Encoding.model_rebuild()

These calls resolve forward references after all models are defined. Without them, self-referential models (Schema → Schema, Operation → PathItem) would fail validation.

14.4 `APIDocumentation`

# core/sillo/openapi/_builder.py:39-798
class APIDocumentation:
    def __init__(
        self,
        config: OpenAPIConfig | None = None,
        swagger_url: str = "/docs",
        redoc_url: str = "/redoc",
        openapi_url: str = "/openapi.json",
    ):

APIDocumentation is the document builder. It walks all registered routes, generates OpenAPI operations, and produces the final spec dictionary.

14.4.1 `get_openapi()`

# _builder.py:92-125
def get_openapi(
    self, route: Route | Router | Group | Any, current_prefix: str = ""
) -> dict[str, Any]:
    self._validator_memo = {}
    routes_with_paths = self._collect_routes_with_paths(route, current_prefix)
    for full_path, route_obj in routes_with_paths:
        if isinstance(route_obj, Route) and not getattr(
            route_obj, "exclude_from_schema", False
        ):
            self._add_route_to_openapi_spec(full_path, route_obj)
    spec = self.config.openapi_spec.model_dump(
        by_alias=True, exclude_none=True, mode="json"
    )
    self._validator_memo = {}
    return spec

Flow:

flowchart TD
    A["get_openapi(root_route)"] --> B["_collect_routes_with_paths(root, '')"]
    B --> C["List of (full_path, Route)"]
    C --> D{"For each route:"}
    D -->|"exclude_from_schema"| E["Skip"]
    D -->|"Normal"| F["_add_route_to_openapi_spec(path, route)"]
    F --> G["Build Operation"]
    G --> H["Add to paths dict"]
    H --> I["model_dump(by_alias, exclude_none, mode='json')"]
    I --> J["Return spec dict"]

The mode="json" parameter is critical: without it, Pydantic’s rich types (AnyUrl, datetime) would appear as Python objects that json.dumps refuses to serialize.

14.4.2 `_collect_routes_with_paths()`

# _builder.py:127-183
def _collect_routes_with_paths(
    self, route: Route | Router | Group | Any, current_prefix: str = ""
) -> list[tuple[str, Route]]:

Recursively flattens the route hierarchy into (full_path, Route) pairs. Handles three container types:

flowchart TD
    A["_collect_routes_with_paths(route, prefix)"] --> B{"Route type?"}
    B -->|"Route"| C["Return [(prefix + raw_path, route)]"]
    B -->|"Router"| D["Add router prefix<br/>Recurse into sub-routes"]
    B -->|"Group"| E["Add group path<br/>Recurse into _base_app or routes"]
    B -->|"Other"| F["Recurse into .routes"]

Prefix handling: The method avoids double-counting prefixes when a router is mounted via a Group:

# _builder.py:146-148
if router_prefix and current_prefix.endswith(router_prefix):
    new_prefix = current_prefix  # Don't add prefix again
else:
    new_prefix = self._normalize_path(current_prefix + router_prefix)

14.4.3 `_add_route_to_openapi_spec()`

# _builder.py:235-274
def _add_route_to_openapi_spec(self, full_path: str, route: Route) -> None:
    openapi_path = self._convert_path_to_openapi_format(full_path)
    for method in sorted(route.methods):
        request_body_spec = self._build_request_body_spec(route, method)
        responses_spec = self._build_responses_spec(route)
        parameters = self._build_parameters_spec(route)

        operation = Operation(
            summary=route.summary or f"{method.upper()} {openapi_path}",
            description=route.description,
            responses=responses_spec,
            tags=route.tags or [],
            parameters=parameters,
            requestBody=request_body_spec,
            security=self._route_security(route),
            operationId=route.operation_id or ...,
            deprecated=route.deprecated,
            externalDocs=getattr(route, "external_docs", None),
        )

        if openapi_path not in self.config.openapi_spec.paths:
            self.config.openapi_spec.paths[openapi_path] = PathItem()
        setattr(
            self.config.openapi_spec.paths[openapi_path], method.lower(), operation
        )

For each HTTP method on the route, it builds:

Parameters: path, query, header, cookie
Request body: JSON or form
Responses: success model + error responses
Security: from route declaration or auth gate

14.4.4 `_build_request_body_spec()`

# _builder.py:283-341
def _build_request_body_spec(self, route: Route, method: str) -> RequestBody | None:

Request bodies come from two sources:

flowchart TD
    A["_build_request_body_spec(route, method)"] --> B["_build_marker_body_spec(route)"]
    B -->|"Found form/file markers"| C["Return form RequestBody"]
    B -->|"None"| D{"route.request_model?"}
    D -->|"BaseModel"| E["model_json_schema() → RequestBody"]
    D -->|"dict"| F["Extract first model from dict"]
    D -->|"None"| G{"Method has body?"}
    G -->|"POST/PUT/PATCH"| H["Default JSON body"]
    G -->|"GET/DELETE/HEAD"| I["None"]

`_build_marker_body_spec()`

# _builder.py:343-384
def _build_marker_body_spec(self, route: Route) -> RequestBody | None:
    for validator in self._collect_validators(route):
        if validator.form_spec is None:
            continue
        spec = validator.form_spec
        raw = spec.model.model_json_schema(by_alias=True, ref_template="#/$defs/{model}")
        schema_dict = self._extract_and_add_nested_schemas(raw)
        properties = dict(schema_dict.get("properties") or {})
        for alias in spec.passthrough.values():
            properties[alias] = {"type": "string", "format": "binary"}
        schema_dict["properties"] = properties
        content_type = (
            "multipart/form-data" if spec.passthrough
            else "application/x-www-form-urlencoded"
        )
        return RequestBody(
            required=True,
            content={content_type: MediaType(spec=Schema(**schema_dict))},
        )
    return None

File markers (passthrough) get {"type": "string", "format": "binary"} in the schema. The content type is multipart/form-data when files are present, application/x-www-form-urlencoded otherwise.

14.4.5 `_extract_and_add_nested_schemas()`

# _builder.py:439-463
def _extract_and_add_nested_schemas(self, schema: dict[str, Any]) -> dict[str, Any]:
    cleaned_schema = copy.deepcopy(schema)
    nested = cleaned_schema.pop("$defs", None)
    if nested:
        for def_name, def_schema in nested.items():
            processed_schema = self._extract_and_add_nested_schemas(def_schema)
            self.config.add_schema(def_name, Schema(**processed_schema))
    self._update_schema_references(cleaned_schema)
    return cleaned_schema

Pydantic puts nested model definitions under $defs. This method:

Deep copies the schema (the caller’s copy is not mutated)
Extracts $defs and registers each as a components.schemas entry
Recursively processes nested $defs (models referencing models)
Rewrites $ref pointers from #/$defs/X to #/components/schemas/X

14.4.6 `_update_schema_references()`

# _builder.py:465-497
def _update_schema_references(self, schema: Any) -> None:
    if isinstance(schema, dict):
        # Handle discriminator mappings
        discriminator = schema.get("discriminator")
        if isinstance(discriminator, dict):
            mapping = discriminator.get("mapping")
            if isinstance(mapping, dict):
                for name, target in mapping.items():
                    if isinstance(target, str) and target.startswith("#/$defs/"):
                        mapping[name] = target.replace("#/$defs/", "#/components/schemas/")

        for key, value in schema.items():
            if key == "$ref" and isinstance(value, str) and value.startswith("#/$defs/"):
                schema[key] = value.replace("#/$defs/", "#/components/schemas/")
            else:
                self._update_schema_references(value)
    elif isinstance(schema, list):
        for item in schema:
            self._update_schema_references(item)

This recursive rewriter handles:

$ref values in any position
Discriminator mapping values (plain strings, not $ref objects)
Nested dicts and lists at any depth

14.4.7 `_build_parameters_spec()`

# _builder.py:609-660
def _build_parameters_spec(self, route: Route) -> list[Parameter]:
    parameters = []
    documented: set = set()

    # Path parameters from compiled validators
    path_schemas: dict[str, Schema] = {}
    for validator in self._collect_validators(route):
        for spec in validator.specs:
            if spec.location is not ParameterLocation.PATH:
                continue
            for name, schema in self._schemas_for_spec(spec).items():
                path_schemas[name] = schema

    # Generic path parameters (from route pattern)
    for param_name in route.param_names:
        parameters.append(OpenAPIPath(
            name=param_name, required=True,
            spec=path_schemas.get(param_name, Schema(type="string")),
        ))
        documented.add(("path", param_name))

    # Legacy parameters
    if hasattr(route, "resolved_params") and route.resolved_params:
        for param_dep in route.resolved_params:
            openapi_param = self._convert_param_dependency(param_dep)
            if openapi_param:
                parameters.append(openapi_param)
                documented.add((openapi_param.in_, openapi_param.name))

    # Validated parameters from compiled models
    for validator in self._collect_validators(route):
        for spec in validator.specs:
            if spec.location is ParameterLocation.PATH:
                continue
            parameters.extend(self._convert_location_spec(spec, documented))

    return parameters

Parameters come from three sources, merged with deduplication:

Compiled validators. Pydantic models with real schemas (constraints, types)
Legacy extractors: schema inferred from default values
Route pattern: path parameters from the URL pattern itself

14.4.8 `_route_security()`

# _builder.py:185-214
def _route_security(self, route: Any) -> Any:
    if route.security is not None:
        return route.security

    gate = getattr(route, "auth", None)
    derive = getattr(gate, "security_requirements", None)
    if not callable(derive):
        return None

    return derive(available=list(self.config.security_schemes))

Security requirements come from:

Explicit security= on the route
Auth gate’s security_requirements(): gates like useAuth() that reject anonymous callers without naming a scheme get filled in with all registered schemes

14.4.9 `_collect_validators()`

# _builder.py:572-607
def _collect_validators(self, route: Route) -> list[Any]:
    key = id(route)
    cached = self._validator_memo.get(key)
    if cached is not None:
        return cached

    validators = []
    dependants = [getattr(route, "dependant", None)]
    dependants.extend(getattr(route, "_router_dependants", []) or [])

    for dependant in dependants:
        if dependant is None:
            continue
        for _, validator in getattr(dependant, "_validator_plan", ()):
            validators.append(validator)

    self._validator_memo[key] = validators
    return validators

Collects every CompiledValidator reachable from a route: including those on nested dependencies. Results are memoized per build since the parameter, request-body, and response sections all need the same list.

14.4.10 Response Building: `_build_responses_spec()`

# _builder.py:386-437
def _build_responses_spec(self, route: Route) -> dict[str, OpenAPIResponse | Reference]:

Response specs are built from (in priority order):

response_model: takes the 200 slot; response_model_many wraps it in list[]
responses dict: explicit status-code-to-model mapping
Default: generic 200 with example object

# For BaseModel response models
schema_dict = model.model_json_schema()
processed_schema = self._extract_and_add_nested_schemas(schema_dict)
example = model.model_validate({}).model_dump(exclude_none=True)

14.4.11 Schema Inference from Defaults

# _builder.py:764-798
def _infer_schema_from_default(self, default: Any) -> Schema:
    if default is ... or default is None:
        return Schema(type="string")

    type_map = {int: "integer", float: "number", bool: "boolean", str: "string"}
    type_default = type(default)
    if type_default in type_map:
        schema = Schema(type=type_map[type_default])
        if default is not None:
            schema.default = default
        if type_default is float:
            schema.format = "float"
        return schema

    if isinstance(default, list):
        return Schema(type="array", items=Schema(type="string"))

    return Schema(type="string")

Legacy parameters (no type=, no constraints) get their schema inferred from the default value’s runtime type. This is the same heuristic used by _convert() for coercion.

14.5 Documentation UIs

14.5.1 `DocsUI` Base Class

# core/sillo/openapi/ui.py:75-151
class DocsUI:
    path: str = "/docs"
    name: str = "docs"

    def __init__(
        self,
        *,
        path: str | None = None,
        title: str | None = None,
        favicon_url: str | None = None,
    ) -> None:

Attribute	Type	Description
`path`	`str`	Where the page is served. Must begin with `/`.
`name`	`str`	Short identifier for error messages and lookup.
`title`	`str \| None`	Browser tab title override.
`favicon_url`	`str \| None`	Icon URL.

`render(ctx)` Method

def render(self, ctx: DocsContext) -> str:
    raise NotImplementedError

Subclasses return a complete HTML document as a string. The DocsContext provides openapi_url (already mount-aware), title, version, description, and the full OpenAPIConfig.

14.5.2 `DocsContext`

# ui.py:53-72
@dataclass(frozen=True)
class DocsContext:
    openapi_url: str
    title: str
    version: str
    description: str
    config: OpenAPIConfig

A frozen dataclass passed to render(). The openapi_url is already prefixed with the request’s root_path, so pages work correctly when the application is mounted under a prefix.

14.5.3 `Atlas`

# ui.py:170-242
class Atlas(DocsUI):
    path = "/docs"
    name = "atlas"

    def __init__(
        self,
        *,
        path: str | None = None,
        title: str | None = None,
        favicon_url: str | None = DEFAULT_FAVICON,
        js_url: str = ATLAS_JS,
        theme: str = "auto",
        ui_config: dict[str, Any] | None = None,
    ) -> None:

Atlas is sillo’s own OpenAPI reference viewer: a three-pane reference with a request builder, ranked search, and snippets in nine languages.

Key features:

Zero dependencies: one script tag
Carries its own styles
Pinned CDN version (v0.8.0) for reproducibility
ui_config merged into createApiReference() call

Render output: Single HTML page with <div id="app"> and Atlas.createApiReference('#app', options).

14.5.4 `Swagger`

# ui.py:245-317
class Swagger(DocsUI):
    path = "/docs"
    name = "swagger"

    def __init__(
        self,
        *,
        path: str | None = None,
        js_url: str = SWAGGER_JS,
        css_url: str = SWAGGER_CSS,
        ui_config: dict[str, Any] | None = None,
        ...
    ) -> None:

Standard Swagger UI. ui_config is passed to SwaggerUIBundle.

Render output: HTML with swagger-ui-bundle.js, swagger-ui.css, and SwaggerUIBundle(options) on window.onload.

14.5.5 `ReDoc`

# ui.py:320-376
class ReDoc(DocsUI):
    path = "/redoc"
    name = "redoc"

    def __init__(
        self,
        *,
        js_url: str = REDOC_JS,
        ui_config: dict[str, Any] | None = None,
        ...
    ) -> None:

ReDoc. ui_config is passed to Redoc.init().

Render output: HTML with redoc.standalone.js and Redoc.init(url, options, element).

14.5.6 `Scalar`

# ui.py:379-446
class Scalar(DocsUI):
    path = "/reference"
    name = "scalar"

    def __init__(
        self,
        *,
        js_url: str = SCALAR_JS,
        theme: str = "default",
        ui_config: dict[str, Any] | None = None,
        ...
    ) -> None:

Scalar API Reference. Uses Scalar.createApiReference() (the current API; older <script id="api-reference"> forms are not supported).

14.5.7 `default_docs()`

# ui.py:449-467
def default_docs(swagger_url: str = "/docs", redoc_url: str = "/redoc") -> list[DocsUI]:
    return [Atlas(path=swagger_url), ReDoc(path=redoc_url)]

The presenters mounted when docs is not given. Returns a fresh list (callers mutate their own copy).

14.6 CDNs and Asset URLs

# ui.py:153-167
DEFAULT_FAVICON = "https://docs.sillo.build/favicon.svg"
ATLAS_VERSION = "v0.8.0"
ATLAS_JS = f"https://cdn.jsdelivr.net/gh/sillohq/atlas@{ATLAS_VERSION}/dist/atlas.standalone.js"
SWAGGER_JS = "https://unpkg.com/swagger-ui-dist@5/swagger-ui-bundle.js"
SWAGGER_CSS = "https://unpkg.com/swagger-ui-dist@5/swagger-ui.css"
REDOC_JS = "https://cdn.redoc.ly/redoc/latest/bundles/redoc.standalone.js"
SCALAR_JS = "https://cdn.jsdelivr.net/npm/@scalar/api-reference"

Atlas is pinned to a specific tag. Other viewers use major-version pins or latest. Override js_url / css_url to self-host for environments with no outbound network or strict CSP.

14.7 Document Serialization

# _builder.py:121-123
spec = self.config.openapi_spec.model_dump(
    by_alias=True, exclude_none=True, mode="json"
)

Three flags matter:

Flag	Purpose
`by_alias=True`	Serialize `$ref` as `$ref` (not `ref`), `in` as `in` (not `in_`).
`exclude_none=True`	Omit optional fields not set: keeps the spec clean.
`mode="json"`	Convert rich types (`AnyUrl`, `datetime`) to JSON-native values. Without this, `json.dumps` fails on `AnyUrl` objects.

14.8 Path Normalization

# _builder.py:216-233
def _normalize_path(self, path: str) -> str:
    if not path:
        return "/"
    if not path.startswith("/"):
        path = "/" + path
    path = re.sub(r"/+", "/", path)
    if len(path) > 1 and path.endswith("/"):
        path = path.rstrip("/")
    return path

14.8.1 Path Format Conversion

# _builder.py:276-281
def _convert_path_to_openapi_format(self, path: str) -> str:
    return re.sub(r"\{(\w+):[^}]+\}", r"{\1}", path)

Sillo’s path format (/users/{id:int}) is converted to OpenAPI format (/users/{id}). The type constraint in the URL pattern is stripped; validation is handled by Path markers instead.

14.9 `get_openapi()` Utility

# core/sillo/openapi/utils.py:7-47
def get_openapi(route: Route | Router | Group | Any) -> list[Route]:
    routes_list: list[Route] = []
    if isinstance(route, Route):
        return [route]
    if isinstance(route, Router):
        for sub_route in route.routes:
            routes_list.extend(get_openapi(sub_route))
        return routes_list
    if isinstance(route, Group):
        if hasattr(route, "_base_app") and isinstance(route._base_app, Router):
            routes_list.extend(get_openapi(route._base_app))
        elif hasattr(route, "routes"):
            for sub_route in route.routes:
                routes_list.extend(get_openapi(sub_route))
        return routes_list
    if hasattr(route, "routes"):
        for sub_route in route.routes:
            routes_list.extend(get_openapi(sub_route))
    return routes_list

A simpler utility that flattens the route hierarchy into a flat list of Route objects without building a document. Used for inspection and testing.

14.10 Complete Build Flow

sequenceDiagram
    participant App as SilloApp
    participant AD as APIDocumentation
    participant Config as OpenAPIConfig
    participant Builder as Route Builder
    participant Spec as OpenAPI Model

    App->>AD: get_openapi(root_router)
    AD->>AD: _collect_routes_with_paths(root, "")
    AD-->>AD: [(full_path, Route), ...]

    loop For each route
        AD->>AD: _add_route_to_openapi_spec(path, route)
        AD->>AD: _build_parameters_spec(route)
        Note over AD: Collect validators, extract schemas
        AD->>AD: _build_request_body_spec(route, method)
        Note over AD: JSON body or form body
        AD->>AD: _build_responses_spec(route)
        Note over AD: response_model or responses dict
        AD->>AD: _route_security(route)
        Note over AD: Explicit or from auth gate
        AD->>AD: Create Operation object
        AD->>Config: paths[path].method = operation
    end

    AD->>Spec: model_dump(by_alias, exclude_none, mode="json")
    Spec-->>AD: dict[str, Any]
    AD-->>App: OpenAPI spec dict

    App->>App: Serve at /openapi.json
    App->>App: Mount DocsUI presenters

14.11 Integration with Validation

The OpenAPI system reads from the same CompiledValidator objects used for runtime validation. This is the mechanism that keeps documentation and enforcement in sync:

# _builder.py:662-681
def _schemas_for_spec(self, spec):
    raw = spec.model.model_json_schema(by_alias=True, ref_template="#/$defs/{model}")
    processed = self._extract_and_add_nested_schemas(raw)
    return {
        name: Schema(**prop)
        for name, prop in (processed.get("properties") or {}).items()
    }

The model_json_schema() call produces the same JSON Schema that Pydantic uses internally for validation. Constraints declared on markers (gt, ge, min_length, pattern) appear in both the documented schema and the runtime validator because they come from the same FieldInfo objects.

14.12 Performance Characteristics

Operation	When	Cost
`get_openapi()`	Once (startup)	O(routes × models)
`_collect_routes_with_paths`	Once	O(route tree depth)
`_add_route_to_openapi_spec`	Once per route	O(validators)
`_extract_and_add_nested_schemas`	Once per model	O($defs depth)
`model_dump()`	Once	O(total spec size)
Serving `/openapi.json`	Per request	O(1): static dict

The document is built once and served as a pre-serialized dict. No per-request computation is needed.

OpenAPI

14.1 Architecture Overview

14.2 OpenAPIConfig

14.2.1 Constructor Fields

14.2.2 Internal State

14.2.3 Component Registration Methods

add_security_scheme(name, scheme)

add_schema(name, schema)

add_parameter(name, parameter)

add_response(name, response)

add_example(name, example)

add_tag(tag)

14.2.4 Additional Methods

14.2.5 Security Schemes Property

14.3 Pydantic OpenAPI 3.0 Models

14.3.1 Document Root

14.3.2 Info Block

14.3.3 Path and Operation

14.3.4 Schema

14.3.5 Parameter Models

14.3.6 Security Scheme Models

14.3.7 Components

14.3.8 Model Rebuilds

14.4 APIDocumentation

14.4.1 get_openapi()

14.4.2 _collect_routes_with_paths()

14.4.3 _add_route_to_openapi_spec()

14.4.4 _build_request_body_spec()

_build_marker_body_spec()

14.4.5 _extract_and_add_nested_schemas()

14.4.6 _update_schema_references()

14.4.7 _build_parameters_spec()

14.4.8 _route_security()

14.4.9 _collect_validators()

14.4.10 Response Building: _build_responses_spec()

14.4.11 Schema Inference from Defaults

14.5 Documentation UIs

14.5.1 DocsUI Base Class

render(ctx) Method

14.5.2 DocsContext

14.5.3 Atlas

14.5.4 Swagger

14.5.5 ReDoc

14.5.6 Scalar

14.5.7 default_docs()