Import code from internal repository to git

java/com/google/domain/registry/request/RequestParameters.java

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+// Copyright 2016 Google Inc. All Rights Reserved.
+//
+// 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
+//
+//     http://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.
+
+package com.google.domain.registry.request;
+
+import static com.google.common.base.Strings.emptyToNull;
+import static com.google.common.base.Strings.isNullOrEmpty;
+import static com.google.common.base.Strings.nullToEmpty;
+
+import com.google.common.base.Ascii;
+import com.google.common.base.Optional;
+import com.google.common.collect.ImmutableSet;
+import com.google.common.net.InetAddresses;
+import com.google.domain.registry.request.HttpException.BadRequestException;
+
+import org.joda.time.DateTime;
+
+import java.net.InetAddress;
+
+import javax.annotation.Nullable;
+import javax.servlet.http.HttpServletRequest;
+
+/** Utilities for extracting parameters from HTTP requests. */
+public final class RequestParameters {
+
+  /** The standardized request parameter name used by any servlet that takes a tld parameter. */
+  public static final String PARAM_TLD = "tld";
+
+  /**
+   * Returns first GET or POST parameter associated with {@code name}.
+   *
+   * <p>For example, assume {@code name} is "bar". The following request URIs would cause this
+   * method to yield the following results:
+   *
+   * <ul>
+   * <li>/foo?bar=hello → hello
+   * <li>/foo?bar=hello&bar=there → hello
+   * <li>/foo?bar= → 400 error (empty)
+   * <li>/foo?bar=&bar=there → 400 error (empty)
+   * <li>/foo → 400 error (absent)
+   * </ul>
+   *
+   * @throws BadRequestException if request parameter is absent or empty
+   */
+  public static String extractRequiredParameter(HttpServletRequest req, String name) {
+    String result = req.getParameter(name);
+    if (isNullOrEmpty(result)) {
+      throw new BadRequestException("Missing parameter: " + name);
+    }
+    return result;
+  }
+
+  /**
+   * Returns first GET or POST parameter associated with {@code name}.
+   *
+   * @throws BadRequestException if request parameter is absent (but not if empty)
+   */
+  public static String extractRequiredMaybeEmptyParameter(HttpServletRequest req, String name) {
+    String result = req.getParameter(name);
+    if (result == null) {
+      throw new BadRequestException("Missing parameter: " + name);
+    }
+    return result;
+  }
+
+  /** Returns the first GET or POST parameter associated with {@code name}. */
+  public static Optional<String> extractOptionalParameter(HttpServletRequest req, String name) {
+    return Optional.fromNullable(emptyToNull(req.getParameter(name)));
+  }
+
+  /**
+   * Returns first GET or POST parameter associated with {@code name} as an integer.
+   *
+   * @throws BadRequestException if request parameter is present but not a valid integer
+   */
+  public static Optional<Integer> extractOptionalIntParameter(HttpServletRequest req, String name) {
+    String stringParam = req.getParameter(name);
+    try {
+      return isNullOrEmpty(stringParam)
+          ? Optional.<Integer>absent()
+          : Optional.of(Integer.valueOf(stringParam));
+    } catch (NumberFormatException e) {
+      throw new BadRequestException("Expected integer: " + name);
+    }
+  }
+
+  /**
+   * Returns first GET or POST parameter associated with {@code name} as an integer.
+   *
+   * @throws BadRequestException if request parameter is absent, empty, or not a valid integer
+   */
+  public static int extractIntParameter(HttpServletRequest req, String name) {
+    try {
+      return Integer.valueOf(nullToEmpty(req.getParameter(name)));
+    } catch (NumberFormatException e) {
+      throw new BadRequestException("Expected integer: " + name);
+    }
+  }
+
+  /** Returns all GET or POST parameters associated with {@code name}. */
+  public static ImmutableSet<String> extractSetOfParameters(HttpServletRequest req, String name) {
+    String[] parameters = req.getParameterValues(name);
+    return parameters == null ? ImmutableSet.<String>of() : ImmutableSet.copyOf(parameters);
+  }
+
+  /**
+   * Returns the first GET or POST parameter associated with {@code name}.
+   *
+   * @throws BadRequestException if request parameter named {@code name} is absent, empty, or not
+   *     equal to any of the values in {@code enumClass}
+   */
+  public static <C extends Enum<C>>
+      C extractEnumParameter(HttpServletRequest req, Class<C> enumClass, String name) {
+    try {
+      return Enum.valueOf(enumClass, Ascii.toUpperCase(extractRequiredParameter(req, name)));
+    } catch (IllegalArgumentException e) {
+      throw new BadRequestException(
+          String.format("Invalid %s parameter: %s", enumClass.getSimpleName(), name));
+    }
+  }
+
+  /**
+   * Returns {@code true} if parameter is present and not empty and not {@code "false"}.
+   *
+   * <p>This considers a parameter with a non-existent value true, for situations where the request
+   * URI is something like {@code /foo?bar}, where the mere presence of the {@code bar} parameter
+   * without a value indicates that it's true.
+   */
+  public static boolean extractBooleanParameter(HttpServletRequest req, String name) {
+    return req.getParameterMap().containsKey(name)
+        && !equalsFalse(req.getParameter(name));
+  }
+
+  /**
+   * Returns first request parameter associated with {@code name} parsed as an
+   * <a href="https://goo.gl/pk5Q2k">ISO 8601</a> timestamp, e.g. {@code 1984-12-18TZ},
+   * {@code 2000-01-01T16:20:00Z}.
+   *
+   * @throws BadRequestException if request parameter named {@code name} is absent, empty, or could
+   *     not be parsed as an ISO 8601 timestamp
+   */
+  public static DateTime extractRequiredDatetimeParameter(HttpServletRequest req, String name) {
+    String stringValue = extractRequiredParameter(req, name);
+    try {
+      return DateTime.parse(stringValue);
+    } catch (IllegalArgumentException e) {
+      throw new BadRequestException("Bad ISO 8601 timestamp: " + name);
+    }
+  }
+
+  /**
+   * Returns first request parameter associated with {@code name} parsed as an optional
+   * {@link InetAddress} (which might be IPv6).
+   *
+   * @throws BadRequestException if request parameter named {@code name} is present but could not
+   *     be parsed as an {@link InetAddress}
+   */
+  public static Optional<InetAddress> extractOptionalInetAddressParameter(
+      HttpServletRequest req, String name) {
+    Optional<String> paramVal = extractOptionalParameter(req, name);
+    if (!paramVal.isPresent()) {
+      return Optional.absent();
+    }
+    try {
+      return Optional.of(InetAddresses.forString(paramVal.get()));
+    } catch (IllegalArgumentException e) {
+      throw new BadRequestException("Not an IPv4 or IPv6 address: " + name);
+    }
+  }
+
+  private static boolean equalsFalse(@Nullable String value) {
+    return nullToEmpty(value).equalsIgnoreCase("false");
+  }
+
+  /**
+   * Returns first HTTP header associated with {@code name}.
+   *
+   * @param name case insensitive header name
+   * @throws BadRequestException if request header is absent or empty
+   */
+  public static String extractRequiredHeader(HttpServletRequest req, String name) {
+    String result = req.getHeader(name);
+    if (isNullOrEmpty(result)) {
+      throw new BadRequestException("Missing header: " + name);
+    }
+    return result;
+  }
+
+  private RequestParameters() {}
+}