httk.serve.optimade.backend.memory_store

A generic in-memory store implementing the httk store/searcher protocols.

Rows are plain dicts keyed by backend record keys, and search expressions evaluate as predicates over those rows. It is the reference Store implementation: it backs the example demo server and is what adapter_from_providers() loads an EntryProvider’s records into.

Set operations evaluate exactly here — has_any/has_only are plain set predicates over the row’s list value, and ~ negates them directly. The SQL backend needs an aggregate rendering and a second (HAVING) evaluation position to say the same thing, but that is entirely its own business: the neutral protocol only ever hands a store one expression per searcher.add call.

String matching is literal here too (contains/startswith/endswith are plain str operations), which is exactly what the neutral protocol promises — no pattern language is involved at any point.

Iteration yields SearchResult values, one entry in values per MemorySearcher.output() call: a variable output yields the whole row dict, a field output the row’s value for that field.

Attributes

Row
Predicate

Classes

MemoryExpression
MemoryField
MemoryVariable	A query variable over one table of rows; attribute access yields fields.
MemorySearcher
InMemoryStore	A store over dict rows: InMemoryStore({'structures': [ {...}, ... ]}).
MemoryResultSet

Module Contents

httk.serve.optimade.backend.memory_store.Row

httk.serve.optimade.backend.memory_store.Predicate

class httk.serve.optimade.backend.memory_store.MemoryExpression(predicate: Predicate)

predicate

class httk.serve.optimade.backend.memory_store.MemoryField(name: str)

name

startswith(other: str) → MemoryExpression

endswith(other: str) → MemoryExpression

contains(other: str) → MemoryExpression

is_in(*values: Any) → MemoryExpression

Match a scalar field against one of the supplied values.

has(value: Any) → MemoryExpression

has_any(*values: Any) → MemoryExpression

has_only(*values: Any) → MemoryExpression

class httk.serve.optimade.backend.memory_store.MemoryVariable(target: str)

A query variable over one table of rows; attribute access yields fields.

always_true/always_false are real methods, declared before the catch-all __getattr__ so they win over it — they are reserved names that never resolve to a row key.

target

always_true() → MemoryExpression

always_false() → MemoryExpression

class httk.serve.optimade.backend.memory_store.MemorySearcher(tables: dict[str, list[Row]])

offset = 0

variable(target: Any) → MemoryVariable

output(variable: MemoryVariable | MemoryField, name: str) → None

Append an output: a variable (yields the whole row) or a field (its value).

add(expression: MemoryExpression) → None

add_sort(field: MemoryField, descending: bool) → None

count() → int

set_limit(limit: int) → None

add_offset(offset: int) → None

results(**outputs: Any) → httk.data.query.ResultSetLike

class httk.serve.optimade.backend.memory_store.InMemoryStore(tables: dict[str, list[Row]])

A store over dict rows: InMemoryStore({'structures': [ {...}, ... ]}).

tables

searcher() → MemorySearcher

class httk.serve.optimade.backend.memory_store.MemoryResultSet(rows: list[Row], outputs: list[tuple[str, MemoryVariable | MemoryField]])

first() → httk.data.query.ResultRowLike | None

one() → httk.data.query.ResultRowLike

scalars(name: str | None = None) → collections.abc.Iterator[Any]

abstractmethod column(name: str) → NoReturn

abstractmethod cursor() → NoReturn