@azure/static-web-apps-cli
Version:
Azure Static Web Apps CLI
125 lines • 6.22 kB
JavaScript
import chalk from "chalk";
import fs from "node:fs";
import path from "node:path";
import { swaCLIEnv } from "../../../core/env.js";
import { logger } from "../../../core/utils/logger.js";
import { globToRegExp, isValidGlobExpression } from "../../../core/utils/glob.js";
import { AUTH_STATUS } from "../../../core/constants.js";
import { doesRequestPathMatchRoute } from "../route-processor.js";
import { getIndexHtml } from "./routes.js";
// See: https://docs.microsoft.com/azure/static-web-apps/configuration#fallback-routes
export function navigationFallback(req, res, navigationFallback) {
let originlUrl = req.url;
logger.silly("checking navigation fallback...");
// don't process .auth requests
if (originlUrl?.startsWith("/.auth")) {
logger.silly(` - request ${chalk.yellow(originlUrl)} is auth`);
logger.silly(` - ignoring navigation fallback`);
return false;
}
// exit if no rewrite rule provided
if (!navigationFallback?.rewrite) {
logger.silly(` - rewrite rule is invalid (got: ${chalk.yellow(navigationFallback?.rewrite)})`);
logger.silly(` - ignoring navigation fallback`);
return false;
}
// exit if no exclude property provided, or exclude list is empty
if (!navigationFallback?.exclude || navigationFallback?.exclude?.length === 0) {
logger.silly(` - exclude rule is invalid (got: ${chalk.yellow(navigationFallback?.exclude)})`);
logger.silly(` - ignoring navigation fallback`);
return false;
}
// make sure we have a leading / in the URL
if (navigationFallback.rewrite.startsWith("/") === false) {
navigationFallback.rewrite = `/${navigationFallback.rewrite}`;
}
// is the requested file available on disk?
const filename = getIndexHtml(originlUrl);
const filepath = path.join(swaCLIEnv().SWA_CLI_OUTPUT_LOCATION, filename);
const isFileFoundOnDisk = fs.existsSync(filepath);
logger.silly(` - url: ${chalk.yellow(originlUrl)}`);
logger.silly(` - file: ${chalk.yellow(filepath)} (exists: ${chalk.yellow(isFileFoundOnDisk)})`);
// parse the exclusion rules and match at least one rule
const isMatchedExcludeRule = navigationFallback?.exclude?.some((filter) => {
if (isValidGlobExpression(filter) === false) {
logger.silly(` - invalid rule ${chalk.yellow(filter)}`);
logger.silly(` - mark as no match`);
return false;
}
// we don't support full globs in the config file.
// add this little utility to convert a wildcard into a valid glob pattern
const regexp = new RegExp(`^${globToRegExp(filter)}$`);
const isMatch = regexp.test(originlUrl);
logger.silly(` - rule: ${chalk.yellow(filter)}`);
logger.silly(` - regexp: ${chalk.yellow(regexp)}`);
logger.silly(` - isRegexpMatch: ${chalk.yellow(isMatch)}`);
return isMatch;
});
logger.silly(` - isMatchedExcludeRule: ${chalk.yellow(isMatchedExcludeRule)}`);
// rules logic:
// 1. if no exclude rules are provided, rewrite by default
// 2. if a file exists on disk, and match exclusion => return it
// 3. if a file doesn't exist on disk, and match exclusion => 404
// 4. if a file exists on disk, and doesn't match exclusion => /index.html
// 5. if a file doesn't exist on disk, and doesn't match exclusion => /index.html
// note: given the complexity of all possible combinations, don't refactor the code below
let rewriteUrl = req.url;
// 1.
if (!navigationFallback.exclude || navigationFallback.exclude.length === 0) {
rewriteUrl = navigationFallback.rewrite;
logger.silly(` - no exclude rules are provided (rewrite by default)`);
logger.silly(` - url: ${chalk.yellow(rewriteUrl)}`);
}
// 2.
else if (isFileFoundOnDisk === true && isMatchedExcludeRule === true) {
rewriteUrl = req.url;
logger.silly(` - file exists on disk, and match exclusion`);
logger.silly(` - url: ${chalk.yellow(rewriteUrl)}`);
}
// 3.
else if (isFileFoundOnDisk === false && isMatchedExcludeRule === true) {
res.statusCode = 404;
logger.silly(` - file doesn't exist on disk, and match exclusion`);
logger.silly(` - statusCode: ${chalk.yellow(404)}`);
}
// 4.
else if (isFileFoundOnDisk === true && isMatchedExcludeRule === false) {
rewriteUrl = navigationFallback.rewrite;
logger.silly(` - file exists on disk, and doesn't match exclusion`);
logger.silly(` - url: ${chalk.yellow(rewriteUrl)}`);
}
// 5.
else if (isFileFoundOnDisk === false && isMatchedExcludeRule === false) {
rewriteUrl = navigationFallback.rewrite;
logger.silly(` - file doesn't exist on disk, and doesn't match exclusion`);
logger.silly(` - url: ${chalk.yellow(rewriteUrl)}`);
}
req.url = rewriteUrl;
return true;
}
export function isRequestPathExcludedFromNavigationFallback(normalizedDecodedRequestPath, navigationFallback, matchedRoute) {
logger.silly(`checking if request is excluded from navigation fallback`);
logger.silly(` - request: ${chalk.yellow(normalizedDecodedRequestPath)}`);
const excludedPathRules = navigationFallback?.exclude;
if (!normalizedDecodedRequestPath || excludedPathRules?.length === 0) {
logger.silly(` - exclude: ${chalk.yellow(false)}`);
return false;
}
const isMatchedExcludeRule = excludedPathRules?.some((filter) => {
// override the route with the current filter rule
const excludedPath = {
...matchedRoute,
route: filter,
};
logger.silly(` - excludedPath: ${chalk.yellow(filter)}`);
return doesRequestPathMatchRoute(normalizedDecodedRequestPath, excludedPath, null, null, AUTH_STATUS.NoAuth);
});
if (isMatchedExcludeRule) {
logger.silly(` - don't rewrite ${chalk.yellow(normalizedDecodedRequestPath)}`);
}
else {
logger.silly(` - rewrite ${chalk.yellow(normalizedDecodedRequestPath)} to ${chalk.yellow(navigationFallback?.rewrite)}`);
}
return isMatchedExcludeRule;
}
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