Add HttpURL with Path and Query inner classes

2 files changed, 384 insertions, 0 deletions

diff --git a/container-core/src/main/java/com/yahoo/restapi/HttpURL.java b/container-core/src/main/java/com/yahoo/restapi/HttpURL.java
new file mode 100644
index 00000000000..8ad1e9fa9ea
--- /dev/null
+++ b/container-core/src/main/java/com/yahoo/restapi/HttpURL.java
@@ -0,0 +1,352 @@
+// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.restapi;
+
+import ai.vespa.validation.StringWrapper;
+import com.yahoo.net.DomainName;
+
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.OptionalInt;
+import java.util.StringJoiner;
+import java.util.function.Function;
+
+import static ai.vespa.validation.Validation.require;
+import static ai.vespa.validation.Validation.requireInRange;
+import static java.net.URLDecoder.decode;
+import static java.net.URLEncoder.encode;
+import static java.nio.charset.StandardCharsets.UTF_8;
+import static java.util.Collections.unmodifiableMap;
+import static java.util.Objects.requireNonNull;
+import static java.util.function.Function.identity;
+
+/**
+ * This is the best class for creating, manipulating and inspecting HTTP URLs, because:
+ * <ul>
+ *     <li>It is more restrictive than {@link URI}, but with a richer construction API, reducing risk of blunder.
+ *         <ul>
+ *             <li>Scheme must be HTTP or HTTPS.</li>
+ *             <li>Authority must be a {@link DomainName}, with an optional port.</li>
+ *             <li>{@link Path} must be normalized at all times.</li>
+ *             <li>Only {@link Query} is allowed, in addition to the above.</li>
+ *         </ul>
+ *     </li>
+ *     <li>
+ *         It contains all those helpful builder methods that {@link URI} has none of.
+ *         <ul>
+ *             <li>{@link Path} can be parsed, have segments or other paths appended, and cut.</li>
+ *             <li>{@link Query} can be parsed, and keys and key-value pairs can be inserted or removed.</li>
+ *         </ul>
+ *         All these (except the parse methods) operate on <em>decoded</em> values.
+ *     </li>
+ *     <li>It makes it super-easy to use a {@link StringWrapper} for validation of path and query segments.</li>
+ * </ul>
+ *
+ * @author jonmv
+ */
+public class HttpURL<T> {
+
+    private final Scheme scheme;
+    private final DomainName domain;
+    private final int port;
+    private final Path<T> path;
+    private final Query<T> query;
+
+    private HttpURL(Scheme scheme, DomainName domain, int port, Path<T> path, Query<T> query) {
+        this.scheme = requireNonNull(scheme);
+        this.domain = requireNonNull(domain);
+        this.port = requireInRange(port, "port number", -1, (1 << 16) - 1);
+        this.path = requireNonNull(path);
+        this.query = requireNonNull(query);
+    }
+
+    public static <T> HttpURL<T> create(Scheme scheme, DomainName domain, int port, Path<T> path, Query<T> query) {
+        return new HttpURL<>(scheme, domain, port, path, query);
+    }
+
+    public static HttpURL<String> create(Scheme scheme, DomainName domain, int port, Path<String> path) {
+        return create(scheme, domain, port, path, Query.empty());
+    }
+
+    public static <T extends StringWrapper<T>> HttpURL<T> create(Scheme scheme, DomainName domain, int port, Path<T> path, Function<String, T> validator) {
+        return create(scheme, domain, port, path, Query.empty(validator));
+    }
+
+    public static <T extends StringWrapper<T>> HttpURL<T> create(Scheme scheme, DomainName domain, int port, Function<String, T> validator) {
+        return create(scheme, domain, port, Path.empty(validator), validator);
+    }
+
+    public static HttpURL<String> create(Scheme scheme, DomainName domain, int port) {
+        return create(scheme, domain, port, Path.empty());
+    }
+
+    public static <T extends StringWrapper<T>> HttpURL<T> create(Scheme scheme, DomainName domain, Function<String, T> validator) {
+        return create(scheme, domain, -1, validator);
+    }
+
+    public static HttpURL<String> create(Scheme scheme, DomainName domain) {
+        return create(scheme, domain, -1);
+    }
+
+    public static HttpURL<String> from(URI uri) {
+        return from(uri, identity(), identity());
+    }
+
+    public static <T extends StringWrapper<T>> HttpURL<T> from(URI uri, Function<String, T> validator) {
+        return from(uri, validator, T::value);
+    }
+
+    private static <T> HttpURL<T> from(URI uri, Function<String, T> validator, Function<T, String> inverse) {
+        if ( ! uri.normalize().equals(uri))
+            throw new IllegalArgumentException("uri should be normalized, but got: " + uri);
+
+        return create(Scheme.of(uri.getScheme()),
+                      DomainName.of(uri.getHost()),
+                      uri.getPort(),
+                      Path.parse(uri.getRawPath(), validator, inverse),
+                      Query.parse(uri.getRawQuery(), validator, inverse));
+    }
+
+    public HttpURL<T> withScheme(Scheme scheme) {
+        return create(scheme, domain, port, path, query);
+    }
+
+    public HttpURL<T> withDomain(DomainName domain) {
+        return create(scheme, domain, port, path, query);
+    }
+
+    public HttpURL<T> withPath(Path<T> path) {
+        return create(scheme, domain, port, path, query);
+    }
+
+    public HttpURL<T> withQuery(Query<T> query) {
+        return create(scheme, domain, port, path, query);
+    }
+
+    public Scheme scheme() {
+        return scheme;
+    }
+
+    public DomainName domain() {
+        return domain;
+    }
+
+    public OptionalInt port() {
+        return port == -1 ? OptionalInt.empty() : OptionalInt.of(port);
+    }
+
+    public Path<T> path() {
+        return path;
+    }
+
+    public Query<T> query() {
+        return query;
+    }
+
+    /** Returns an absolute, hierarchical URI representing this HTTP URL. */
+    public URI asURI() {
+        try {
+            return new URI(scheme.name() + "://" + domain.value() + (port == -1 ? "" : ":" + port) + path.raw() + query.raw());
+        }
+        catch (URISyntaxException e) {
+            throw new IllegalStateException("invalid URI, this should not happen", e);
+        }
+    }
+
+
+    public static class Path<T> {
+
+        private final List<T> segments;
+        private final boolean trailingSlash;
+        private final Function<String, T> validator;
+        private final Function<T, String> inverse;
+
+        private Path(List<T> segments, boolean trailingSlash, Function<String, T> validator, Function<T, String> inverse) {
+            this.segments = requireNonNull(segments);
+            this.trailingSlash = trailingSlash;
+            this.validator = requireNonNull(validator);
+            this.inverse = requireNonNull(inverse);
+        }
+
+        /** Creates a new, empty path, with a trailing slash. */
+        public static <T extends StringWrapper<T>> Path<T> empty(Function<String, T> validator) {
+            return new Path<>(List.of(), true, validator, T::value);
+        }
+
+        /** Creates a new, empty path, with a trailing slash. */
+        public static Path<String> empty() {
+            return new Path<>(List.of(), true, identity(), identity());
+        }
+
+        /** Parses the given raw, normalized path string; this ignores whether the path is absolute or relative. */
+        public static <T extends StringWrapper<T>> Path<T> parse(String raw, Function<String, T> validator) {
+            return parse(raw, validator, T::value);
+        }
+
+        /** Parses the given raw, normalized path string; this ignores whether the path is absolute or relative. */
+        public static Path<String> parse(String raw) {
+            return parse(raw, identity(), identity());
+        }
+
+        private static <T> Path<T> parse(String raw, Function<String, T> validator, Function<T, String> inverse) {
+            boolean trailingSlash = raw.endsWith("/");
+            if (raw.startsWith("/")) raw = raw.substring(1);
+            if (raw.isEmpty()) return new Path<>(List.of(), trailingSlash, validator, inverse);
+            List<T> segments = new ArrayList<>();
+            for (String segment : raw.split("/"))
+                segments.add(validator.apply(requireNormalized(decode(segment, UTF_8))));
+            if (segments.size() == 0) requireNormalized(""); // Raw path was only slashes.
+            return new Path<>(segments, trailingSlash, validator, inverse);
+        }
+
+        private static String requireNormalized(String segment) {
+            return require( ! (segment.isEmpty() || segment.equals(".") || segment.equals("..")),
+                           segment, "path segments cannot be \"\", \".\", or \"..\"");
+        }
+
+        /** Returns a copy of this which eliminates the given number of segments, from the root down. */
+        public Path<T> tailPath(int offset) {
+            return new Path<>(segments.subList(offset, segments.size()), trailingSlash, validator, inverse);
+        }
+
+        /** Returns a copy of this which eliminates the given number of segments, from the end up. */
+        public Path<T> headPath(int offset) {
+            return new Path<>(segments.subList(0, segments.size() - offset), trailingSlash, validator, inverse);
+        }
+
+        /** Returns a copy of this with the <em>decoded</em> segment appended at the end; it may not be either of {@code ""}, {@code "."} or {@code ".."}. */
+        public Path<T> with(T segment) {
+            List<T> copy = new ArrayList<>(segments);
+            copy.add(segment);
+            return new Path<>(copy, trailingSlash, validator, inverse);
+        }
+
+        /** Returns a copy of this all segments of the other path appended, with a trailing slash as per the appendage. */
+        public <U> Path<T> with(Path<U> other) {
+            List<T> copy = new ArrayList<>(segments);
+            for (U segment : other.segments)
+                copy.add(validator.apply(other.inverse.apply(segment)));
+            return new Path<>(copy, other.trailingSlash, validator, inverse);
+        }
+
+        /** Returns a copy of this which encodes a trailing slash. */
+        public Path<T> withTrailingSlash() {
+            return new Path<>(segments, true, validator, inverse);
+        }
+
+        /** Returns a copy of this which does not encode a trailing slash. */
+        public Path<T> withoutTrailingSlash() {
+            return new Path<>(segments, false, validator, inverse);
+        }
+
+        /** The URL decoded segments that make up this path; never {@code ""}, {@code "."} or {@code ".."}. */
+        public List<T> decoded() {
+            return Collections.unmodifiableList(segments);
+        }
+
+        /** A raw path string which parses to this, by splitting on {@code "/"}, and then URL decoding. */
+        private String raw() {
+            StringJoiner joiner = new StringJoiner("/", "/", trailingSlash ? "/" : "").setEmptyValue(trailingSlash ? "/" : "");
+            for (T segment : segments)
+                joiner.add(encode(inverse.apply(segment), UTF_8));
+            return joiner.toString();
+        }
+
+    }
+
+
+    public static class Query<T> {
+
+        private final Map<T, T> values;
+        private final Function<String, T> validator;
+        private final Function<T, String> inverse;
+
+        private Query(Map<T, T> values, Function<String, T> validator, Function<T, String> inverse) {
+            this.values = requireNonNull(values);
+            this.validator = requireNonNull(validator);
+            this.inverse = requireNonNull(inverse);
+        }
+
+        /** Parses the given raw query string. */
+        public static <T extends StringWrapper<T>> Query<T> parse(String raw, Function<String, T> validator) {
+            return parse(raw, validator, T::value);
+        }
+
+        /** Parses the given raw query string. */
+        public static Query<String> parse(String raw) {
+            return parse(raw, identity(), identity());
+        }
+
+        private static <T> Query<T> parse(String raw, Function<String, T> validator, Function<T, String> inverse) {
+            if (raw == null) return new Query<>(Map.of(), validator, inverse);
+            Map<T, T> values = new LinkedHashMap<>();
+            for (String pair : raw.split("&")) {
+                int split = pair.indexOf("=");
+                String key, value;
+                if (split == -1) { key = pair; value = null; }
+                else { key = pair.substring(0, split); value = pair.substring(split + 1); }
+                values.put(validator.apply(decode(key, UTF_8)), value == null ? null : validator.apply(decode(value, UTF_8)));
+            }
+            return new Query<>(values, validator, inverse);
+        }
+
+        public static <T extends StringWrapper<T>> Query<T> empty(Function<String, T> validator) {
+            return new Query<T>(Map.of(), validator, T::value);
+        }
+
+        public static <T> Query<String> empty() {
+            return new Query<>(Map.of(), identity(), identity());
+        }
+
+        /** Returns a copy of this with the <em>decoded</em> non-null key pointing to the <em>decoded</em> non-null value. */
+        public Query<T> with(T key, T value) {
+            Map<T, T> copy = new LinkedHashMap<>(values);
+            copy.put(requireNonNull(key), value);
+            return new Query<>(copy, validator, inverse);
+        }
+
+        /** Returns a copy of this with the <em>decoded</em> non-null key pointing to "nothing". */
+        public Query<T> with(T key) {
+            Map<T, T> copy = new LinkedHashMap<>(values);
+            copy.put(requireNonNull(key), null);
+            return new Query<>(copy, validator, inverse);
+        }
+
+        /** Returns a copy of this without any key-value pair with the <em>decoded</em> key. */
+        public Query<T> without(T key) {
+            Map<T, T> copy = new LinkedHashMap<>(values);
+            copy.remove(key);
+            return new Query<>(copy, validator, inverse);
+        }
+
+        /** The URL decoded key-value pairs that make up this query; keys and values may be {@code ""}, and values are {@code} null if only key was specified. */
+        public Map<T, T> decoded() {
+            return unmodifiableMap(values);
+        }
+
+        /** A raw query string, with {@code '?'} prepended, that parses to this, by splitting on {@code "&"}, then on {@code "="}, and then URL decoding; or the empty string if this is empty. */
+        private String raw() {
+            StringJoiner joiner = new StringJoiner("&", "?", "").setEmptyValue("");
+            values.forEach((key, value) -> joiner.add(encode(inverse.apply(key), UTF_8) +
+                                                      (value == null ? "" : "=" + encode(inverse.apply(value), UTF_8))));
+            return joiner.toString();
+        }
+
+    }
+
+
+    public enum Scheme {
+        http,
+        https;
+        public static Scheme of(String scheme) {
+            if (scheme.equalsIgnoreCase(http.name())) return http;
+            if (scheme.equalsIgnoreCase(https.name())) return https;
+            throw new IllegalArgumentException("scheme must be HTTP or HTTPS");
+        }
+    }
+
+}
diff --git a/container-core/src/test/java/com/yahoo/restapi/HttpURLTest.java b/container-core/src/test/java/com/yahoo/restapi/HttpURLTest.java
new file mode 100644
index 00000000000..00da850d739
--- /dev/null
+++ b/container-core/src/test/java/com/yahoo/restapi/HttpURLTest.java
@@ -0,0 +1,32 @@
+// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.restapi;
+
+import org.junit.jupiter.api.Test;
+
+import java.net.URI;
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+/**
+ * @author jonmv
+ */
+class HttpURLTest {
+
+    @Test
+    void testConversion() {
+        for (String uri : List.of("http://minimal",
+                                  "http://empty.query?",
+                                  "http://zero-port:0?no=path",
+                                  "http://only-path/",
+                                  "https://strange/queries?=&foo",
+                                  "https://weirdness?=foo",
+                                  "https://encoded/%3F%3D%26%2F?%3F%3D%26%2F=%3F%3D%26%2F",
+                                  "https://host.at.domain:123/one/two/?three=four&five"))
+            assertEquals(uri, HttpURL.from(URI.create(uri)).asURI().toString(),
+                         "uri '" + uri + "' should be returned unchanged");
+    }
+
+}