ContentEnricherLoader.java
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 org.apache.tika.config.loader;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.node.ObjectNode;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.tika.exception.TikaConfigException;
import org.apache.tika.parser.ParseContext;
import org.apache.tika.parser.Parser;
import org.apache.tika.parser.ParserDecorator;
import org.apache.tika.parser.enricher.CompositeContentEnricher;
import org.apache.tika.parser.enricher.ContentEnrichers;
import org.apache.tika.parser.enricher.GatedEnricher;
import org.apache.tika.parser.enricher.ImageCheck;
import org.apache.tika.parser.enricher.RecordedSizeCheck;
import org.apache.tika.parser.enricher.TextRecognizer;
import org.apache.tika.parser.inference.Engine;
import org.apache.tika.parser.inference.EngineRegistry;
/**
* Loads {@code "text-recognizers"}. An entry either names an engine from {@code "engines"}
* ({@code {"engine": "tesseract", "_mime-include": [...]}}) or carries the engine inline
* ({@code {"tesseract-ocr-parser": {...}}}), the 4.0 form. An empty list is authoritative;
* an absent key means the recognizers are resolved from the loaded parsers.
*/
class ContentEnricherLoader implements ComponentLoader<CompositeContentEnricher> {
static final String KEY = "text-recognizers";
private static final Logger LOG = LoggerFactory.getLogger(ContentEnricherLoader.class);
private static final Set<String> REFERENCE_KEYS = Set.of("engine", "_mime-include",
"_mime-exclude", "min-width", "min-height", "_min-width", "_min-height", "checks");
/** Directives of this list only: removed from an inline entry's engine settings. */
private static final List<String> ENTRY_DIRECTIVES = List.of("min-width", "min-height",
"checks");
@Override
public CompositeContentEnricher load(TikaJsonConfig config, LoaderContext context)
throws TikaConfigException {
JsonNode node = config.getRootNode().get(KEY);
if (node == null) {
return null;
}
if (!node.isArray()) {
throw new TikaConfigException("\"" + KEY + "\" must be an array");
}
List<Parser> enrichers = new ArrayList<>();
ParseContext empty = new ParseContext();
for (JsonNode item : node) {
String label;
Parser enricher;
if (item.isObject() && item.has("engine")) {
label = "engine \"" + item.get("engine").asText() + "\"";
enricher = gated(referenced(item, context), item, label, context);
} else {
Map.Entry<String, JsonNode> entry = inline(item, context);
label = "\"" + entry.getKey() + "\"";
enricher = gated(instantiate(withoutDirectives(entry), context), entry.getValue(), label,
context);
}
// lifetime snapshot: an empty engine must fail load, not go inert; ask the
// engine itself, since a _mime-include answers for the decorator
if (unwrap(enricher).getSupportedTypes(empty).isEmpty()) {
throw new TikaConfigException("Text recognizer " + label
+ " advertises no media types (a _mime-include list does not "
+ "count). Is the engine unavailable (missing native binary, "
+ "unreachable inference server) or configured to skip enrichment?");
}
// an engine that declines to recognize (a VLM with textRecognizer false) warns too
TextRecognizer recognizer = ContentEnrichers.asTextRecognizer(enricher);
if ((recognizer == null || !recognizer.recognizesText(empty))
&& !advertisesLegacyOcr(enricher)) {
LOG.warn("\"text-recognizers\" entry {} recognizes no text; it runs as an "
+ "annotator on the images and pages it is offered (4.3 gives annotators "
+ "a list of their own)", label);
}
enrichers.add(enricher);
}
return new CompositeContentEnricher(enrichers);
}
/** The engine the entry names, from {@code "engines"}, behind the entry's mime filters. */
private static Parser referenced(JsonNode item, LoaderContext context)
throws TikaConfigException {
Iterator<String> names = item.fieldNames();
while (names.hasNext()) {
String name = names.next();
if (!REFERENCE_KEYS.contains(name)) {
throw new TikaConfigException("\"" + KEY + "\" entry naming an engine has "
+ "unknown key \"" + name + "\"; known: " + REFERENCE_KEYS
+ ". The engine's own settings belong under \"engines\".");
}
}
JsonNode nameNode = item.get("engine");
if (!nameNode.isTextual()) {
throw new TikaConfigException("\"" + KEY + "\" entry: \"engine\" must be a name "
+ "from \"engines\"");
}
String engineName = nameNode.asText();
EngineRegistry engines = context.get(EngineRegistry.class);
Engine engine = engines == null ? null : engines.get(engineName);
if (engine == null) {
throw new TikaConfigException("\"" + KEY + "\" entry names engine \"" + engineName
+ "\", which is not in \"engines\"");
}
if (!(engine instanceof Parser parser) || !ContentEnrichers.isEnricher(parser)) {
throw new TikaConfigException("\"" + KEY + "\" entry names engine \"" + engineName
+ "\" (" + engine.getClass().getName() + "), which is not a text "
+ "recognizer: a recognizer implements ContentEnricher");
}
return ComponentInstantiator.withMimeFilters(parser, item);
}
/**
* The entry's {@code min-width}/{@code min-height} (or the older {@code _min-width}/{@code
* _min-height}, same meaning); null when neither is set. An image of
* unknown size passes the gate, and one below {@link ContentEnrichers#MIN_PIXELS} never
* reaches dispatch anyway.
*/
private static int[] sizeGate(JsonNode settings, String label) throws TikaConfigException {
if (!settings.isObject()) {
return null;
}
Integer minWidth = minimum(settings, "min-width", label);
Integer minHeight = minimum(settings, "min-height", label);
if (minWidth == null && minHeight == null) {
return null;
}
return new int[] {minWidth == null ? 0 : minWidth, minHeight == null ? 0 : minHeight};
}
/**
* The engine behind its entry's checks: the recorded-size minimum, then the {@code checks},
* in order, in one decorator; the engine itself when the entry has none.
*/
private static Parser gated(Parser enricher, JsonNode settings, String label,
LoaderContext context) throws TikaConfigException {
List<ImageCheck> checks = new ArrayList<>();
int[] gate = sizeGate(settings, label);
if (gate != null) {
checks.add(new RecordedSizeCheck(gate[0], gate[1]));
}
checks.addAll(namedChecks(settings, label, context));
return checks.isEmpty() ? enricher : new GatedEnricher(enricher, checks);
}
/** The entry's {@code checks}: component names, or {@code {"name": {settings}}}. */
private static List<ImageCheck> namedChecks(JsonNode settings, String label,
LoaderContext context)
throws TikaConfigException {
List<ImageCheck> checks = new ArrayList<>();
JsonNode list = settings.isObject() ? settings.get("checks") : null;
if (list == null) {
return checks;
}
if (!list.isArray()) {
throw new TikaConfigException("\"" + KEY + "\" entry " + label
+ ": \"checks\" must be an array");
}
for (JsonNode item : list) {
Map.Entry<String, JsonNode> check;
try {
check = inline(item, context);
} catch (TikaConfigException e) {
throw new TikaConfigException("\"" + KEY + "\" entry " + label
+ ": a \"checks\" member is a name or {\"name\": {...}}; got " + item);
}
checks.add(ComponentInstantiator.instantiateComponent(check.getKey(),
check.getValue(), context.getObjectMapper(), context.getClassLoader(),
ImageCheck.class, true));
}
return checks;
}
/** The value of {@code field} or its older {@code _field} spelling; both is an error. */
private static Integer minimum(JsonNode settings, String field, String label)
throws TikaConfigException {
String alias = "_" + field;
if (settings.has(field) && settings.has(alias)) {
throw new TikaConfigException("\"" + KEY + "\" entry " + label + " sets both \""
+ field + "\" and its older spelling \"" + alias + "\"; use one");
}
String name = settings.has(field) ? field : alias;
JsonNode v = settings.get(name);
if (v == null) {
return null;
}
if (!v.isIntegralNumber() || v.asInt() < 0) {
throw new TikaConfigException("\"" + KEY + "\" entry " + label + ": \"" + name
+ "\" must be a non-negative integer");
}
return v.asInt();
}
/** The 4.0 form: {@code "name"} or {@code {"name": {...}}}, first field only. */
private static Map.Entry<String, JsonNode> inline(JsonNode item, LoaderContext context)
throws TikaConfigException {
if (item.isTextual()) {
return Map.entry(item.asText(), (JsonNode) context.getObjectMapper().createObjectNode());
}
if (item.isObject() && item.size() == 1) {
Map.Entry<String, JsonNode> first = item.fields().next();
return Map.entry(first.getKey(), first.getValue());
}
throw new TikaConfigException("\"" + KEY + "\" entries are {\"engine\": \"<name>\"} "
+ "or {\"<recognizer>\": {...}}; got " + item);
}
/**
* The inline entry without this list's own directives ({@code min-width}, {@code
* min-height}, {@code checks}): they are directives here only, so they are removed for this
* entry's engine and no other component loses a setting of that name.
*/
private static Map.Entry<String, JsonNode> withoutDirectives(
Map.Entry<String, JsonNode> entry) {
if (!(entry.getValue() instanceof ObjectNode settings)
|| ENTRY_DIRECTIVES.stream().noneMatch(settings::has)) {
return entry;
}
ObjectNode copy = settings.deepCopy();
ENTRY_DIRECTIVES.forEach(copy::remove);
return Map.entry(entry.getKey(), copy);
}
private static Parser instantiate(Map.Entry<String, JsonNode> entry, LoaderContext context)
throws TikaConfigException {
try {
ObjectNode wrapper = context.getObjectMapper().createObjectNode();
wrapper.set(entry.getKey(), entry.getValue());
return context.getObjectMapper().treeToValue(wrapper, Parser.class);
} catch (Exception e) {
throw new TikaConfigException("Failed to load text recognizer: " + entry.getKey(), e);
}
}
private static Parser unwrap(Parser parser) {
while (parser instanceof ParserDecorator decorator) {
parser = decorator.getWrappedParser();
}
return parser;
}
// a pre-4.1 engine advertising image/ocr-* counts as a recognizer until 5.0
private static boolean advertisesLegacyOcr(Parser enricher) {
for (org.apache.tika.mime.MediaType type
: unwrap(enricher).getSupportedTypes(new ParseContext())) {
if (ContentEnrichers.isLegacyOcrType(type)) {
return true;
}
}
return false;
}
}