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✨ add CF function for getting SLUG.config.json
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@danyx23
danyx23 committed Aug 28, 2024
1 parent 9cea8aa commit c735b81
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Showing 2 changed files with 178 additions and 39 deletions.
70 changes: 60 additions & 10 deletions functions/_common/grapherRenderer.ts
View file
Original file line number Diff line number Diff line change
Expand Up @@ -158,14 +158,17 @@ async function fetchFromR2(
return primaryResponse
}

async function fetchAndRenderGrapherToSvg(
slug: string,
options: ImageOptions,
searchParams: URLSearchParams,
env: Env
) {
const grapherLogger = new TimeLogger("grapher")
interface FetchGrapherConfigResult {
grapherConfig: GrapherInterface | null
status: number
etag: string | undefined
}

export async function fetchGrapherConfig(
slug: string,
env: Env,
etag: string
): Promise<FetchGrapherConfigResult> {
// The top level directory is either the bucket path (should be set in dev environments and production)
// or the branch name on preview staging environments
console.log("branch", env.CF_PAGES_BRANCH)
Expand Down Expand Up @@ -206,15 +209,38 @@ async function fetchAndRenderGrapherToSvg(

if (fetchResponse.status !== 200) {
console.log("Failed to fetch grapher config", fetchResponse.status)
return null
return {
grapherConfig: null,
status: fetchResponse.status,
etag: fetchResponse.headers.get("etag"),
}
}

const grapherConfig: GrapherInterface = await fetchResponse.json()
console.log("grapher title", grapherConfig.title)
return {
grapherConfig,
status: 200,
etag: fetchResponse.headers.get("etag"),
}
}

async function fetchAndRenderGrapherToSvg(
slug: string,
options: ImageOptions,
searchParams: URLSearchParams,
env: Env
) {
const grapherLogger = new TimeLogger("grapher")

const grapherConfigResponse = await fetchGrapherConfig(slug, env, etag)

if (grapherConfigResponse.status !== 200) {
return null
}

const bounds = new Bounds(0, 0, options.svgWidth, options.svgHeight)
const grapher = new Grapher({
...grapherConfig,
...grapherConfigResponse.grapherConfig,
bakedGrapherURL: grapherBaseUrl,
queryStr: "?" + searchParams.toString(),
bounds,
Expand Down Expand Up @@ -298,3 +324,27 @@ async function renderSvgToPng(svg: string, options: ImageOptions) {
pngLogger.log("svg2png")
return pngData
}

export async function getOptionalRedirectForSlug(
slug: string,
baseUrl: URL,
env: Env
) {
const redirects: Record<string, string> = await env.ASSETS.fetch(
new URL("/grapher/_grapherRedirects.json", baseUrl),
{ cf: { cacheTtl: 2 * 60 } }
)
.then((r): Promise<Record<string, string>> => r.json())
.catch((e) => {
console.error("Error fetching redirects", e)
return {}
})
return redirects[slug]
}

export function createRedirectResponse(redirSlug: string, currentUrl: URL) {
new Response(null, {
status: 302,
headers: { Location: `/grapher/${redirSlug}${currentUrl.search}` },
})
}
147 changes: 118 additions & 29 deletions functions/grapher/[slug].ts
View file
Original file line number Diff line number Diff line change
@@ -1,33 +1,57 @@
import { Env } from "./thumbnail/[slug].js"
import {
fetchGrapherConfig,
getOptionalRedirectForSlug,
createRedirectResponse,
} from "../_common/grapherRenderer.js"
import { IRequestStrict, Router, error, cors } from "itty-router"

const { preflight, corsify } = cors({
allowMethods: "GET",
})

const router = Router<IRequestStrict, [URL, Env, string]>({
before: [preflight],
finally: [corsify],
})
router
.get(
"/grapher/:slug.config.json",
async ({ params: { slug } }, { searchParams }, env, etag) =>
handleConfigRequest(slug, searchParams, env, etag)
)
.get(
"/grapher/:slug",
async ({ params: { slug } }, { searchParams }, env) =>
handleHtmlPageRequest(slug, searchParams, env)
)
.all("*", () => error(404, "Route not defined"))

export const onRequestGet: PagesFunction = async (context) => {
// Makes it so that if there's an error, we will just deliver the original page before the HTML rewrite.
// Only caveat is that redirects will not be taken into account for some reason; but on the other hand the worker is so simple that it's unlikely to fail.
context.passThroughOnException()
const { request, env } = context
const url = new URL(request.url)

// Redirects handling is performed by the worker, and is done by fetching the (baked) _grapherRedirects.json file.
// That file is a mapping from old slug to new slug.
const getOptionalRedirectForSlug = async (slug: string, baseUrl: URL) => {
const redirects: Record<string, string> = await env.ASSETS.fetch(
new URL("/grapher/_grapherRedirects.json", baseUrl),
{ cf: { cacheTtl: 2 * 60 } }
return router
.fetch(
request,
url,
{ ...env, url },
request.headers.get("if-none-match")
)
.then((r): Promise<Record<string, string>> => r.json())
.catch((e) => {
console.error("Error fetching redirects", e)
return {}
})
return redirects[slug]
}

const createRedirectResponse = (redirSlug: string, currentUrl: URL) =>
new Response(null, {
status: 302,
headers: { Location: `/grapher/${redirSlug}${currentUrl.search}` },
})

const { request, env, params } = context
.catch((e) => error(500, e))
}

const originalSlug = params.slug as string
const url = new URL(request.url)
async function handleHtmlPageRequest(
slug: string,
searchParams: URLSearchParams,
env: Env
) {
const url = env.url
// Redirects handling is performed by the worker, and is done by fetching the (baked) _grapherRedirects.json file.
// That file is a mapping from old slug to new slug.

/**
* REDIRECTS HANDLING:
Expand All @@ -40,11 +64,12 @@ export const onRequestGet: PagesFunction = async (context) => {

// All our grapher slugs are lowercase by convention.
// To allow incoming links that may contain uppercase characters to work, we redirect to the lowercase version.
const lowerCaseSlug = originalSlug.toLowerCase()
if (lowerCaseSlug !== originalSlug) {
const lowerCaseSlug = slug.toLowerCase()
if (lowerCaseSlug !== slug) {
const redirectSlug = await getOptionalRedirectForSlug(
lowerCaseSlug,
url
url,
env
)

return createRedirectResponse(redirectSlug ?? lowerCaseSlug, url)
Expand All @@ -61,8 +86,8 @@ export const onRequestGet: PagesFunction = async (context) => {
if (grapherPageResp.status === 404) {
// If the request is a 404, we check if there's a redirect for it.
// If there is, we redirect to the new page.
const redirectSlug = await getOptionalRedirectForSlug(originalSlug, url)
if (redirectSlug && redirectSlug !== originalSlug) {
const redirectSlug = await getOptionalRedirectForSlug(slug, url, env)
if (redirectSlug && redirectSlug !== slug) {
return createRedirectResponse(redirectSlug, url)
} else {
// Otherwise we just return the 404 page.
Expand Down Expand Up @@ -110,5 +135,69 @@ export const onRequestGet: PagesFunction = async (context) => {
},
})

return rewriter.transform(grapherPageResp)
return rewriter.transform(grapherPageResp as unknown as Response)
}

async function handleConfigRequest(
slug: string,
searchParams: URLSearchParams,
env: Env,
etag: string | undefined
) {
const shouldCache = searchParams.get("nocache") === null
console.log("Preapring json response for ", slug)
// All our grapher slugs are lowercase by convention.
// To allow incoming links that may contain uppercase characters to work, we redirect to the lowercase version.
const lowerCaseSlug = slug.toLowerCase()
if (lowerCaseSlug !== slug) {
const redirectSlug = await getOptionalRedirectForSlug(
lowerCaseSlug,
env.url,
env
)

return createRedirectResponse(
redirectSlug ? `${redirectSlug}.config.json` : lowerCaseSlug,
env.url
)
}

const grapherPageResp = await fetchGrapherConfig(slug, env, etag)

if (grapherPageResp.status === 304) {
return new Response(null, { status: 304 })
}

if (grapherPageResp.status !== 200) {
// If the request is a 404, we check if there's a redirect for it.
// If there is, we redirect to the new page.
const redirectSlug = await getOptionalRedirectForSlug(
slug,
env.url,
env
)
if (redirectSlug && redirectSlug !== slug) {
return createRedirectResponse(
`${redirectSlug}.config.json`,
env.url
)
} else {
// Otherwise we just return the status code.
return new Response(null, { status: grapherPageResp.status })
}
}

console.log("Grapher page response", grapherPageResp.grapherConfig.title)

const cacheControl = shouldCache
? "public, s-maxage=3600, max-age=0, must-revalidate"
: "public, s-maxage=0, max-age=0, must-revalidate"

return new Response(JSON.stringify(grapherPageResp.grapherConfig), {
headers: {
"content-type": "application/json",
"Cache-Control": cacheControl,
ETag: grapherPageResp.etag,
},
})
}

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