@theguild/federation-composition
Version:
Open Source Composition library for Apollo Federation
246 lines (242 loc) • 7.97 kB
JavaScript
import { Kind } from 'graphql';
import JSON5 from 'json5';
import { print } from '../graphql/printer.js';
export function printLink(link) {
return print({
kind: Kind.DIRECTIVE,
name: {
kind: Kind.NAME,
value: 'link',
},
arguments: [
{
kind: Kind.ARGUMENT,
name: {
kind: Kind.NAME,
value: 'url',
},
value: {
kind: Kind.STRING,
value: [link.identity, link.version].filter(Boolean).join('/'),
},
},
{
kind: Kind.ARGUMENT,
name: {
kind: Kind.NAME,
value: 'import',
},
value: {
kind: Kind.LIST,
values: link.imports.map(im => {
if (!im.alias) {
return {
kind: Kind.STRING,
value: im.name,
};
}
return {
kind: Kind.OBJECT,
fields: [
{
kind: Kind.OBJECT_FIELD,
name: {
kind: Kind.NAME,
value: 'name',
},
value: {
kind: Kind.STRING,
value: im.name,
},
},
{
kind: Kind.OBJECT_FIELD,
name: {
kind: Kind.NAME,
value: 'as',
},
value: {
kind: Kind.STRING,
value: im.alias,
},
},
],
};
}),
},
},
],
});
}
export function parseLinkUrl(urlString) {
const url = new URL(urlString);
const parts = url.pathname.split('/').filter(Boolean);
const len = parts.length;
if (!len) {
return { name: null, version: null, identity: url.origin };
}
const last = parts[len - 1];
const secondLast = parts[len - 2];
const potentiallyNameAndVersion = typeof secondLast === 'string';
if (potentiallyNameAndVersion) {
return {
name: secondLast,
version: last,
identity: url.origin +
'/' +
parts
.slice(0, len - 2)
.concat(secondLast)
.join('/'),
};
}
if (/^v\d+/i.test(last)) {
return {
name: null,
version: last,
identity: url.origin,
};
}
return {
name: last,
version: null,
identity: url.origin +
'/' +
parts
.slice(0, len - 2)
.concat(last)
.join('/'),
};
}
export function parseLinkImport(importString) {
try {
const bindings = JSON5.parse(importString);
if (!Array.isArray(bindings)) {
throw new Error(`Expected an array`);
}
return bindings.map(binding => {
if (typeof binding === 'string') {
return {
kind: binding.startsWith('@') ? 'directive' : 'type',
name: binding,
};
}
if (typeof binding === 'object' && binding.name) {
const nameKind = binding.name.startsWith('@') ? 'directive' : 'type';
if (!binding.as) {
return {
kind: nameKind,
name: binding.name,
};
}
const aliasKind = binding.as.startsWith('@') ? 'directive' : 'type';
if (nameKind !== aliasKind) {
throw new Error(`${binding.name} and ${binding.as} must be of the same kind`);
}
return {
kind: nameKind,
name: binding.name,
alias: binding.as,
};
}
throw new Error(`Syntax`);
});
}
catch (error) {
throw new Error(`Invalid import binding: ${importString}: ${String(error)}`);
}
}
export function mergeLinks(links) {
const groupByIdentity = new Map();
for (const link of links) {
const existing = groupByIdentity.get(link.identity);
if (!existing) {
const importedDirectives = link.imports.filter(im => im.kind === 'directive');
if (importedDirectives.length === 0) {
continue;
}
groupByIdentity.set(link.identity, {
name: link.name,
highestVersion: link.version ?? '',
imports: link.imports.filter(im => im.kind === 'directive'),
});
}
else {
if (link.version &&
parseFloat(link.version.replace('v', '')) >
parseFloat(existing.highestVersion.replace('v', ''))) {
existing.highestVersion = link.version;
}
for (const im of link.imports) {
if (im.kind === 'type') {
continue;
}
const hasImport = existing.imports.some(existingIm => existingIm.kind === im.kind && existingIm.name === im.name);
if (!hasImport) {
existing.imports.push(im);
}
}
if (link.name) {
existing.name = link.name;
}
}
}
return Array.from(groupByIdentity.entries()).map(([identity, link]) => ({
identity,
version: link.highestVersion,
imports: Array.from(link.imports).map(link => ({
kind: link.kind,
name: link.name,
alias: link.alias,
})),
name: link.name,
}));
}
export function parseLink(urlString, importString) {
const spec = parseLinkUrl(urlString);
return {
name: spec.name,
version: spec.version,
identity: spec.identity,
imports: parseLinkImport(importString),
};
}
export function parseLinkDirective(directive) {
const urlArg = directive.arguments?.find(isUrlArgument);
if (!urlArg) {
return null;
}
const importArg = directive.arguments?.find(isImportArgument);
const spec = parseLinkUrl(urlArg?.value.value);
return {
name: spec.name,
version: spec.version,
identity: spec.identity,
imports: parseLinkImport(importArg ? print(importArg.value) : '[]'),
};
}
function isUrlArgument(arg) {
return arg.name.value === 'url' && arg.value.kind === Kind.STRING;
}
function isImportArgument(arg) {
return arg.name.value === 'import' && arg.value.kind === Kind.LIST;
}
export const sdl = `
directive @link(
url: String
as: String
for: link__Purpose
import: [link__Import]
) repeatable on SCHEMA
scalar link__Import
enum link__Purpose {
"""
\`SECURITY\` features provide metadata necessary to securely resolve fields.
"""
SECURITY
"""
\`EXECUTION\` features provide metadata necessary for operation execution.
"""
EXECUTION
}
`;