🧹 Restructure CF functions code into smaller files

functions/_common/env.ts

@@ -8,3 +8,14 @@ export interface Env {
     CF_PAGES_BRANCH: string
     ENV: string
 }
+// We collect the possible extensions here so we can easily take them into account
+// when handling redirects
+export const extensions = {
+    configJson: ".config.json",
+    png: ".png",
+    svg: ".svg",
+    csv: ".csv",
+    metadata: ".metadata.json",
+    readme: ".readme.md",
+    zip: ".zip",
+}

functions/_common/fetchMetadataForGrapher.ts

@@ -0,0 +1,138 @@
+import { Grapher } from "@ourworldindata/grapher"
+import { OwidColumnDef } from "@ourworldindata/types"
+import { StatusError } from "itty-router"
+import { createZip } from "littlezipper"
+import { assembleMetadata, getColumnsForMetadata } from "./metadataTools.js"
+import { Env } from "./env.js"
+import { GrapherIdentifier, initGrapher } from "./grapherTools.js"
+import { TWITTER_OPTIONS } from "./imageOptions.js"
+import { constructReadme } from "./readmeTools"
+
+export async function fetchMetadataForGrapher(
+    identifier: GrapherIdentifier,
+    env: Env,
+    searchParams?: URLSearchParams
+) {
+    console.log("Initializing grapher")
+    const grapher = await initGrapher(
+        identifier,
+        TWITTER_OPTIONS,
+        searchParams ?? new URLSearchParams(""),
+        env
+    )
+
+    await grapher.downloadLegacyDataFromOwidVariableIds()
+
+    const fullMetadata = assembleMetadata(
+        grapher,
+        searchParams ?? new URLSearchParams("")
+    )
+
+    return Response.json(fullMetadata)
+}
+
+export async function fetchZipForGrapher(
+    identifier: GrapherIdentifier,
+    env: Env,
+    searchParams?: URLSearchParams
+) {
+    console.log("preparing to generate zip file")
+    const grapher = await initGrapher(
+        identifier,
+        TWITTER_OPTIONS,
+        searchParams ?? new URLSearchParams(""),
+        env
+    )
+    await grapher.downloadLegacyDataFromOwidVariableIds()
+    ensureDownloadOfDataAllowed(grapher)
+    const metadata = assembleMetadata(grapher, searchParams)
+    const readme = assembleReadme(grapher)
+    const csv = assembleCsv(grapher, searchParams)
+    console.log("Fetched the parts, creating zip file")
+
+    const zipContent: File[] = [
+        {
+            path: `${identifier.id}.metadata.json`,
+            data: JSON.stringify(metadata, undefined, 2),
+        },
+        { path: `${identifier.id}.csv`, data: csv },
+        { path: "readme.md", data: readme },
+    ]
+    const content = await createZip(zipContent)
+    console.log("Generated content, returning response")
+    return new Response(content, {
+        headers: {
+            "Content-Type": "application/zip",
+        },
+    })
+}
+function assembleCsv(grapher: Grapher, searchParams: URLSearchParams): string {
+    const useShortNames = searchParams.get("useColumnShortNames") === "true"
+    const table =
+        searchParams.get("csvType") === "filtered"
+            ? grapher.transformedTable
+            : grapher.inputTable
+    return table.toPrettyCsv(useShortNames)
+}
+
+export async function fetchCsvForGrapher(
+    identifier: GrapherIdentifier,
+    env: Env,
+    searchParams?: URLSearchParams
+) {
+    const grapher = await initGrapher(
+        identifier,
+        TWITTER_OPTIONS,
+        searchParams ?? new URLSearchParams(""),
+        env
+    )
+    await grapher.downloadLegacyDataFromOwidVariableIds()
+    console.log("checking if download is allowed")
+    ensureDownloadOfDataAllowed(grapher)
+    console.log("data download is allowed")
+    const csv = assembleCsv(grapher, searchParams ?? new URLSearchParams(""))
+    return new Response(csv, {
+        headers: {
+            "Content-Type": "text/csv",
+        },
+    })
+}
+function ensureDownloadOfDataAllowed(grapher: Grapher) {
+    if (
+        grapher.inputTable.columnsAsArray.some(
+            (col) => (col.def as OwidColumnDef).nonRedistributable
+        )
+    ) {
+        throw new StatusError(
+            403,
+            "This chart contains non-redistributable data that we are not allowed to re-share and it therefore cannot be downloaded as a CSV."
+        )
+    }
+}
+
+export async function fetchReadmeForGrapher(
+    identifier: GrapherIdentifier,
+    env: Env,
+    searchParams?: URLSearchParams
+) {
+    console.log("Initializing grapher")
+    const grapher = await initGrapher(
+        identifier,
+        TWITTER_OPTIONS,
+        searchParams ?? new URLSearchParams(""),
+        env
+    )
+
+    await grapher.downloadLegacyDataFromOwidVariableIds()
+
+    const readme = assembleReadme(grapher)
+    return new Response(readme, {
+        headers: {
+            "Content-Type": "text/markdown; charset=utf-8",
+        },
+    })
+}
+function assembleReadme(grapher: Grapher): string {
+    const metadataCols = getColumnsForMetadata(grapher)
+    return constructReadme(grapher, metadataCols)
+}