apigeelint/lib/package/plugins/ST005-extractFormParamConditionCheck.js

Node module and tool to lint a bundle for an Apigee API Proxy or sharedflow.

/*
  Copyright © 2019-2022,2026 Google LLC

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

      https://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
*/

const ruleId = require("../lintUtil.js").getRuleId(),
  debug = require("debug")("apigeelint:" + ruleId),
  xpath = require("xpath");

const plugin = {
  ruleId,
  name: "Extract Variables with FormParam",
  message:
    "For the ExtractVariables step, an appropriate check for a message body was not found on the enclosing Step or Flow.",
  fatal: false,
  severity: 1, //1=warning, 2=error
  nodeType: "Step",
  enabled: true,
};

const stringNonNullCheckRegexp = (source) =>
  `\\(? *\\b${source}\\b *(!=|NotEquals|IsNot) *(\"\"|null) *\\)?`;

const messageCheckRegexp = (source) =>
  stringNonNullCheckRegexp(`${source}.formstring`);
const paramCheckRegexp = (source, name) =>
  stringNonNullCheckRegexp(`${source}.formparam.${name}`);

const exampleFormstringCondition = (source, _params) =>
  `${source}.formstring != null`;
const exampleParamCondition = (source, params) =>
  params.map((name) => `${source}.formparam.${name} != null`).join(" || ");

const isSufficient = function (condition, source, paramNames) {
  const exp = condition.getExpression();
  debug(`isSufficient cond(${exp})`);
  const retval =
    exp.match(messageCheckRegexp(source)) ||
    paramNames.some((name) => exp.match(paramCheckRegexp(source, name)));
  debug(`> isSufficient() ${!!retval}`);
  return retval;
};

const check = function (endpoint) {
  let flagged = false;
  const bundlePolicies = endpoint.parent.getPolicies();

  endpoint.getSteps().forEach((step) => {
    const referredPolicy = bundlePolicies.find((p) =>
      p.getSteps().find((s) => s == step),
    );
    if (!referredPolicy || referredPolicy.getType() !== "ExtractVariables") {
      return;
    }
    debug("found an attached ExtractVariables policy");
    const formParam = xpath.select(
      `/ExtractVariables/FormParam/text()`,
      referredPolicy.getElement(),
    );
    if (formParam.length == 0) {
      debug(`no extract from FormParam`);
      return;
    }
    debug(`extracts from FormParam (${formParam.length})`);
    const paramNames = xpath
      .select(`/ExtractVariables/FormParam/@name`, referredPolicy.getElement())
      .map((attr) => attr.value);

    debug(`param names: (${paramNames})`);
    const sourceElement = xpath.select(
      "/ExtractVariables/Source/text()",
      referredPolicy.getElement(),
    );

    let source = "will.be.replaced";
    if (sourceElement && sourceElement.length) {
      source = sourceElement[0].data;
    } else {
      // source is empty, ∴ implicitly use "message"
      debug(`Source element is empty`);
      source = "message";
    }

    let condition = step.getCondition();
    if (condition && isSufficient(condition, source, paramNames)) {
      debug("sufficient condition");
      return;
    }
    debug("did not find sufficient condition on step, checking parent...");
    let parent = step.parent;
    if (parent) {
      if (parent.getType() === "FlowPhase") {
        debug(`parent phase: ${parent.getPhase()}`);
        parent = parent.parent;
      }
    }
    if (parent) {
      if (parent.getType() === "Flow") {
        condition = parent.getCondition();
        if (condition) {
          debug(`parent cond expression: [${condition.getExpression()}]`);
          if (isSufficient(condition, source, paramNames)) {
            debug("parent has sufficient condition");
            return true;
          }
          debug("parent does not have sufficient condition");
        } else {
          debug(`no Condition on parent`);
        }
      }
    } else {
      debug(`no parent?`);
    }

    debug("missing or insufficient condition");
    flagged = true;
    const policyName = xpath.select1(
      "/ExtractVariables/@name",
      referredPolicy.getElement(),
    ).value;
    endpoint.addMessage({
      plugin,
      source: step.getElement().toString(),
      line: step.getElement().lineNumber,
      column: step.getElement().columnNumber,
      message: `For the ExtractVariables step (${policyName}), an appropriate check for a message body was not found. For example, use <Condition>${exampleFormstringCondition(source)}</Condition> or <Condition>${exampleParamCondition(source, paramNames)}</Condition>`,
    });
  });

  return flagged;
};

const onProxyEndpoint = function (endpoint, cb) {
  debug("onProxyEndpoint");
  const flagged = check(endpoint);
  if (typeof cb == "function") {
    cb(null, flagged);
  }
};

const onTargetEndpoint = function (endpoint, cb) {
  debug("onTargetEndpoint");
  const flagged = check(endpoint);
  if (typeof cb == "function") {
    cb(null, flagged);
  }
};

module.exports = {
  plugin,
  onProxyEndpoint,
  onTargetEndpoint,
};