Add filter-provided captcha score thresholds

service/src/main/java/org/whispersystems/textsecuregcm/spam/Extract.java

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2023 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.whispersystems.textsecuregcm.spam;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Indicates that a parameter should be parsed from a {@link org.glassfish.jersey.server.ContainerRequest}
+ */
+@Target({ElementType.PARAMETER, ElementType.FIELD})
+@Retention(RetentionPolicy.RUNTIME)
+public @interface Extract {
+
+}

service/src/main/java/org/whispersystems/textsecuregcm/spam/ScoreThreshold.java

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+/*
+ * Copyright 2023 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.whispersystems.textsecuregcm.spam;
+
+import org.glassfish.jersey.server.ContainerRequest;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import java.util.Optional;
+
+/**
+ * A ScoreThreshold may be provided by an upstream request filter. If request contains a property for
+ * SCORE_THRESHOLD_PROPERTY_NAME it can be forwarded to a downstream filter to indicate it can use
+ * a more or less strict score threshold when evaluating whether a request should be allowed to continue.
+ */
+public class ScoreThreshold {
+  private static final Logger logger = LoggerFactory.getLogger(ScoreThreshold.class);
+
+  public static final String PROPERTY_NAME = "scoreThreshold";
+
+  /**
+   * A score threshold in the range [0, 1.0]
+   */
+  private final Optional<Float> scoreThreshold;
+
+  /**
+   * Extract an optional score threshold parameter provided by an upstream request filter
+   */
+  public ScoreThreshold(final ContainerRequest containerRequest) {
+    this.scoreThreshold = Optional
+        .ofNullable(containerRequest.getProperty(PROPERTY_NAME))
+        .flatMap(obj -> {
+          if (obj instanceof Float f) {
+            return Optional.of(f);
+          }
+          logger.warn("invalid format for filter provided score threshold {}", obj);
+          return Optional.empty();
+        });
+  }
+
+  public Optional<Float> getScoreThreshold() {
+    return this.scoreThreshold;
+  }
+}

service/src/main/java/org/whispersystems/textsecuregcm/spam/ScoreThresholdProvider.java

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+package org.whispersystems.textsecuregcm.spam;
+
+import java.util.function.Function;
+import javax.inject.Singleton;
+import javax.ws.rs.core.Feature;
+import javax.ws.rs.core.FeatureContext;
+import org.glassfish.jersey.internal.inject.AbstractBinder;
+import org.glassfish.jersey.server.ContainerRequest;
+import org.glassfish.jersey.server.model.Parameter;
+import org.glassfish.jersey.server.spi.internal.ValueParamProvider;
+
+/**
+ * Parses a {@link ScoreThreshold} out of a {@link ContainerRequest} to provide to jersey resources.
+ *
+ * A request filter may enrich a ContainerRequest with a scoreThreshold by providing a float property with the name
+ * {@link ScoreThreshold#PROPERTY_NAME}. This indicates the desired scoreThreshold to use when evaluating whether a
+ * request should proceed.
+ *
+ * A resource can consume a ScoreThreshold with by annotating a ScoreThreshold parameter with {@link Extract}
+ */
+public class ScoreThresholdProvider implements ValueParamProvider {
+
+  /**
+   * Configures the ScoreThresholdProvider
+   */
+  public static class ScoreThresholdFeature implements Feature {
+    @Override
+    public boolean configure(FeatureContext context) {
+      context.register(new AbstractBinder() {
+        @Override
+        protected void configure() {
+          bind(ScoreThresholdProvider.class)
+              .to(ValueParamProvider.class)
+              .in(Singleton.class);
+        }
+      });
+      return true;
+    }
+  }
+
+  @Override
+  public Function<ContainerRequest, ?> getValueProvider(final Parameter parameter) {
+    if (parameter.getRawType().equals(ScoreThreshold.class)
+        && parameter.isAnnotationPresent(Extract.class)) {
+      return ScoreThreshold::new;
+    }
+    return null;
+
+  }
+
+  @Override
+  public PriorityType getPriority() {
+    return Priority.HIGH;
+  }
+}