import {
buildClientSchema,
getIntrospectionQuery,
GraphQLSchema,
isObjectType,
isInterfaceType,
isInputObjectType,
isEnumType,
isUnionType,
isScalarType,
printSchema,
} from "graphql";
import { readFile } from "node:fs/promises";
/**
* Introspect a GraphQL endpoint and return the schema as the GraphQL SDL
*/
export async function introspectEndpoint(
endpoint: string,
headers?: Record<string, string>,
) {
const response = await fetch(endpoint, {
method: "POST",
headers: { "Content-Type": "application/json", ...headers },
body: JSON.stringify({
query: getIntrospectionQuery(),
}),
});
if (!response.ok) {
throw new Error(`GraphQL request failed: ${response.statusText}`);
}
const responseJson = await response.json();
const schema = buildClientSchema((responseJson as any).data);
return printSchema(schema);
}
/**
* Introspect a local GraphQL schema file
*/
export async function introspectLocalSchema(path: string) {
return await readFile(path, "utf8");
}
/**
* Extract and filter specific types from a schema object.
* Prevents "No result received" errors by only sending requested parts of the graph.
*/
export function introspectSpecificTypes(schema: GraphQLSchema, typeNames: string[]) {
const result: Record<string, any> = {};
for (const name of typeNames) {
const type = schema.getType(name);
if (!type) continue;
if (isObjectType(type) || isInterfaceType(type)) {
result[name] = {
kind: isInterfaceType(type) ? "INTERFACE" : "OBJECT",
description: type.description,
fields: Object.fromEntries(
Object.entries(type.getFields())
.filter(([_, field]) => !field.deprecationReason)
.map(([fieldName, field]) => [
fieldName,
{
type: field.type.toString(),
description: field.description,
args: field.args
.filter(arg => !arg.deprecationReason)
.map(arg => ({
name: arg.name,
type: arg.type.toString(),
description: arg.description,
}))
}
])
)
};
} else if (isInputObjectType(type)) {
result[name] = {
kind: "INPUT_OBJECT",
description: type.description,
fields: Object.fromEntries(
Object.entries(type.getFields())
.filter(([_, field]) => !field.deprecationReason)
.map(([fieldName, field]) => [
fieldName,
{ type: field.type.toString(), description: field.description }
])
)
};
} else if (isEnumType(type)) {
result[name] = {
kind: "ENUM",
description: type.description,
values: type.getValues().map(v => ({
name: v.name,
description: v.description
}))
};
} else if (isUnionType(type)) {
result[name] = {
kind: "UNION",
description: type.description,
possibleTypes: type.getTypes().map(t => t.name)
};
} else if (isScalarType(type)) {
result[name] = {
kind: "SCALAR",
description: type.description
};
}
}
return result;
}
/**
* Backwards compatibility helper for direct endpoint introspection
*/
export async function introspectTypes(
endpoint: string,
headers: Record<string, string> = {},
typeNames: string[]
) {
const response = await fetch(endpoint, {
method: "POST",
headers: { "Content-Type": "application/json", ...headers },
body: JSON.stringify({ query: getIntrospectionQuery() }),
});
const data = await response.json();
const schema = buildClientSchema(data.data);
const result = introspectSpecificTypes(schema, typeNames);
return JSON.stringify(result);
}
