Merge pull request #58 from asibs/jms/democracy_club_lookup

Jms/democracy club lookup

app/api/constituency_lookup/[postcode]/[[...address]]/route.ts

@@ -7,6 +7,62 @@ import { validatePostcode, normalizePostcode } from "@/utils/Postcodes";
 
 // Force using 'nodejs' rather than 'edge' - edge won't have the filesystem containing SQLite
 export const runtime = "nodejs";
+export const revalidate = 3600;
+
+type DCData = {
+  boundary_changes?: {
+    current_constituencies_official_identifier: string;
+    current_constituencies_name: string;
+    new_constituencies_official_identifier: string;
+    new_constituencies_name: string;
+    CHANGE_TYPE: string;
+  };
+  addresses?: {
+    address: string;
+    postcode: string;
+    slug: string;
+    url: string;
+  }[];
+};
+
+const dc_base_url = "https://developers.democracyclub.org.uk/api/v1/";
+const dc_params =
+  "/?" +
+  new URLSearchParams({
+    auth_token: process.env.DC_API_KEY || "",
+    parl_boundaries: "1",
+  }).toString();
+
+async function fetch_dc_api(
+  postcode: string,
+  addressSlug?: string,
+): Promise<DCData | null> {
+  const dc_url =
+    dc_base_url +
+    (addressSlug ? "address/" + addressSlug : "postcode/" + postcode) +
+    dc_params;
+
+  const dc_res = await fetch(dc_url, { signal: AbortSignal.timeout(5000) });
+
+  if (dc_res.ok) {
+    const dc_json = await dc_res.json();
+    if (
+      !addressSlug &&
+      dc_json.address_picker &&
+      dc_json.addresses.length > 0
+    ) {
+      return { addresses: dc_json.addresses };
+    } else if (dc_json.parl_boundary_changes) {
+      return { boundary_changes: dc_json.parl_boundary_changes };
+    } else {
+      console.log("DC No Useful Response", await dc_res.json());
+      return null;
+    }
+  } else {
+    console.log("DC ERROR", await dc_res.text());
+    return null;
+  }
+}
 
 // Declare the DB outside the func & lazy-load, so it can be cached across calls
 let db: Database | null = null;
@@ -52,8 +108,9 @@ export async function GET(
 
   // Query the database
   console.time("query-postcode-database");
-  const constituencies = await db.all(
+  const db_constituencies = await db.all(
     `SELECT
+      pcon.gss,
       pcon.slug,
       pcon.name
     FROM postcode_lookup
@@ -64,7 +121,7 @@ export async function GET(
   );
   console.timeEnd("query-postcode-database");
 
-  if (!constituencies || constituencies.length == 0) {
+  if (!db_constituencies || db_constituencies.length == 0) {
     console.log(`Postcode ${normalizedPostcode} not found in DB!`);
     const response: ConstituencyLookupResponse = {
       postcode: params.postcode,
@@ -75,25 +132,61 @@ export async function GET(
     return NextResponse.json(response);
   }
 
-  if (constituencies.length == 1) {
+  if (db_constituencies.length == 1) {
     console.log(`Single constituency found for postcode ${normalizedPostcode}`);
     const response: ConstituencyLookupResponse = {
       postcode: params.postcode,
       addressSlug: params.address?.[0],
-      constituencies: constituencies,
+      constituencies: db_constituencies,
     };
     return NextResponse.json(response);
   } else {
-    // TODO: Use DemocracyClub API to lookup postcode and populate the addresses array, so users can select their
-    // specific address, rather than us expecting to know (or find out) their constituency.
     console.log(
       `Multiple constituencies found for postcode ${normalizedPostcode}`,
     );
+
     const response: ConstituencyLookupResponse = {
       postcode: params.postcode,
       addressSlug: params.address?.[0],
-      constituencies: constituencies,
+      constituencies: db_constituencies,
     };
+
+    //see if DC api will give us anything useful
+    //TODO remove this if statement, (here so we can test DC API failure!)
+    let dc_data = null;
+    if (normalizedPostcode != "DE30GU")
+      dc_data = await fetch_dc_api(normalizedPostcode, params.address?.[0]);
+
+    //const dc_data = await fetch_dc_api(normalizedPostcode, params.address?.[0]);
+
+    // See if DC data can return a more useful response.
+    // Possibly it just matches 1 constituency in which case return that
+    // Possibly it gives us an address picker which we can return.
+    if (dc_data?.boundary_changes) {
+      //Democracy Club data shows this postcode has a single constituency
+      const gss =
+        dc_data.boundary_changes.new_constituencies_official_identifier.substring(
+          4,
+        );
+      const dc_constituency = db_constituencies.filter((c) => c.gss === gss);
+
+      if (dc_constituency.length === 1) {
+        response.constituencies = dc_constituency;
+      } else {
+        //TODO some way to get vercel to notify us of this error since it shows
+        //a problem in our or DC data (once DC have fixed their NI & Scottish codes)
+        console.error(JSON.stringify(dc_data));
+        console.error(
+          "DC returned boundary change data but it didn't match a single db record??",
+        );
+      }
+    } else if (dc_data?.addresses && dc_data.addresses.length > 0) {
+      response.addresses = dc_data.addresses.map((addr) => ({
+        name: addr.address,
+        slug: addr.slug,
+      }));
+    }
+
     return NextResponse.json(response);
   }
 }

components/constituency_lookup/ConstituencyLookup.tsx

@@ -97,9 +97,11 @@ const throttledApi = async (
   postcode: string,
   addressSlug?: string,
 ): Promise<ConstituencyLookupResponse | null> => {
-  //TODO handle address lookups in the cache if/when we use DemoClub API
-  if (lookupCache.hasOwnProperty(postcode)) {
-    const cached = await lookupCache[postcode];
+  addressSlug = addressSlug || "";
+  const cacheKey = postcode + addressSlug;
+
+  if (!addressSlug && lookupCache.hasOwnProperty(postcode)) {
+    const cached = await lookupCache[cacheKey];
     if (cached) {
       return cached;
     }
@@ -112,16 +114,15 @@ const throttledApi = async (
     lookupCache[reqControl.lastLookup] = null;
   }
 
-  // TODO handle address lookups in the cache.
-  reqControl.lastLookup = postcode;
+  reqControl.lastLookup = cacheKey;
 
   if (reqControl.time + reqControl.rateLimit < Date.now()) {
     //Last request was more than rate limit ago.
     reqControl.time = Date.now();
-    lookupCache[postcode] = fetchApi(postcode, addressSlug);
+    lookupCache[cacheKey] = fetchApi(postcode, addressSlug);
   } else {
     //Need to delay the request.
-    lookupCache[postcode] = new Promise((resolve) => {
+    lookupCache[cacheKey] = new Promise((resolve) => {
       let cancelled: boolean = true;
       reqControl.timerID = setTimeout(
         () => {
@@ -144,7 +145,7 @@ const throttledApi = async (
     });
   }
 
-  return lookupCache[postcode];
+  return lookupCache[cacheKey];
 };
 
 type FormData = {
@@ -206,6 +207,7 @@ const PostcodeLookup = () => {
     setApiResponse(false);
     setPostError(null);
 
+    console.log("Lookup Constituency", postcode, addressSlug);
     const responseJson = await throttledApi(postcode, addressSlug);
 
     if (postcode != validPostcode.current) {
@@ -260,6 +262,10 @@ const PostcodeLookup = () => {
     if (validatePostcode.test(normalizedPostcode)) {
       validPostcode.current = normalizedPostcode;
       await lookupConstituency(normalizedPostcode);
+      return;
+    } else {
+      //Otherwise reset the display of selected postcode
+      setApiResponse(null);
     }
   };
 
@@ -362,33 +368,75 @@ const PostcodeLookup = () => {
         </InputGroup>
 
         {apiResponse && apiResponse.constituencies.length > 1 && (
-          <div className="my-3">
-            <p className="mb-1" style={{ fontSize: "0.75em" }}>
-              We can&apos;t work out exactly which constituency you&apos;re in -
-              please select one of the {apiResponse.constituencies.length}{" "}
-              options:
-            </p>
-            <Form.Select
-              name="constituency"
-              size="lg"
-              defaultValue=""
-              onChange={(e) =>
-                setFormState({
-                  ...formState,
-                  constituencyIndex: parseInt(e.target.value),
-                })
-              }
-            >
-              <option selected disabled value="" style={{ display: "none" }}>
-                Select Constituency
-              </option>
-              {apiResponse.constituencies.map((c, idx) => (
-                <option key={c.slug} value={idx}>
-                  {c.name}
-                </option>
-              ))}
-            </Form.Select>
-          </div>
+          <>
+            {apiResponse.addresses ? (
+              <div className="my-3">
+                <p className="mb-1" style={{ fontSize: "0.75em" }}>
+                  We can&apos;t work out exactly which constituency you&apos;re
+                  in - please select your address:
+                </p>
+                <Form.Select
+                  name="address"
+                  size="lg"
+                  defaultValue=""
+                  onChange={(e) =>
+                    lookupConstituency(validPostcode.current, e.target.value)
+                  }
+                >
+                  <option
+                    selected
+                    disabled
+                    value=""
+                    style={{ display: "none" }}
+                  >
+                    Select Address
+                  </option>
+                  {apiResponse.addresses.map((c) => (
+                    <option key={c.slug} value={c.slug}>
+                      {c.name}
+                    </option>
+                  ))}
+                </Form.Select>
+              </div>
+            ) : (
+              <div className="my-3">
+                <p className="mb-1" style={{ fontSize: "0.75em" }}>
+                  We can&apos;t work out exactly which constituency you&apos;re
+                  in - please select one of the{" "}
+                  {apiResponse.constituencies.length} options:
+                </p>
+                <Form.Select
+                  name="constituency"
+                  size="lg"
+                  defaultValue=""
+                  onChange={(e) => {
+                    if (e.target.value.length > 2) {
+                      lookupConstituency(validPostcode.current, e.target.value);
+                    } else {
+                      setFormState({
+                        ...formState,
+                        constituencyIndex: parseInt(e.target.value),
+                      });
+                    }
+                  }}
+                >
+                  <option
+                    selected
+                    disabled
+                    value=""
+                    style={{ display: "none" }}
+                  >
+                    Select Constituency
+                  </option>
+                  {apiResponse.constituencies.map((c, idx) => (
+                    <option key={c.slug} value={idx}>
+                      {c.name}
+                    </option>
+                  ))}
+                </Form.Select>
+              </div>
+            )}
+          </>
         )}
         {subscribed ? (
           <div className="my-3"></div>

components/constituency_lookup/types.tsx

@@ -5,6 +5,7 @@
 type Constituency = {
   name: string;
   slug: string;
+  gss?: string;
 };
 
 type Address = {