| 164 | } |
| 165 | |
| 166 | async serveFromCache( |
| 167 | req: Request, |
| 168 | res: Response, |
| 169 | next: NextFunction, |
| 170 | config?: ServeFromCacheConfig, |
| 171 | ): Promise<Response | void> { |
| 172 | try { |
| 173 | const variant = getVariant(req, this.isrConfig.variants); |
| 174 | const cacheKey = this.cacheGeneration.getCacheKey( |
| 175 | req.url, |
| 176 | this.isrConfig.allowedQueryParams, |
| 177 | variant, |
| 178 | ); |
| 179 | const cacheData = await this.cache.get(cacheKey); |
| 180 | const { html, options: cacheConfig, createdAt } = cacheData; |
| 181 | |
| 182 | const cacheHasBuildId = |
| 183 | cacheConfig.buildId !== null && cacheConfig.buildId !== undefined; |
| 184 | |
| 185 | if (cacheHasBuildId && cacheConfig.buildId !== this.isrConfig.buildId) { |
| 186 | // Cache is from a different build. Serve user using SSR |
| 187 | next(); |
| 188 | return; |
| 189 | } |
| 190 | |
| 191 | // Cache exists. Send it. |
| 192 | this.logger.log(`Page was retrieved from cache: `, cacheKey); |
| 193 | let finalHtml = html; |
| 194 | |
| 195 | // if the cache is expired, we will regenerate it |
| 196 | if (cacheConfig.revalidate && cacheConfig.revalidate > 0) { |
| 197 | const lastCacheDateDiff = (Date.now() - createdAt) / 1000; // in seconds |
| 198 | |
| 199 | if (lastCacheDateDiff > cacheConfig.revalidate) { |
| 200 | const generate = () => { |
| 201 | return this.cacheGeneration.generateWithCacheKey( |
| 202 | req, |
| 203 | res, |
| 204 | cacheKey, |
| 205 | config?.providers, |
| 206 | 'regenerate', |
| 207 | ); |
| 208 | }; |
| 209 | |
| 210 | try { |
| 211 | // regenerate the page without awaiting, so the user gets the cached page immediately |
| 212 | if (this.isrConfig.backgroundRevalidation) { |
| 213 | generate(); |
| 214 | } else { |
| 215 | const result = await generate(); |
| 216 | if (result?.html) { |
| 217 | finalHtml = result.html; |
| 218 | } |
| 219 | } |
| 220 | } catch (error) { |
| 221 | console.error('Error generating html', error); |
| 222 | next(); |
| 223 | } |