com.github.fge.jsonschema.load.URIManager Maven / Gradle / Ivy

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/*
 * Copyright (c) 2013, Francis Galiegue 
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the Lesser GNU General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * Lesser GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see .
 */

package com.github.fge.jsonschema.load;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.ObjectReader;
import com.github.fge.jsonschema.exceptions.ProcessingException;
import com.github.fge.jsonschema.load.configuration.LoadingConfiguration;
import com.github.fge.jsonschema.messages.JsonSchemaCoreMessageBundle;
import com.github.fge.jsonschema.report.ProcessingMessage;
import com.github.fge.msgsimple.bundle.MessageBundle;
import com.github.fge.msgsimple.load.MessageBundles;

import java.io.IOException;
import java.io.InputStream;
import java.net.URI;
import java.util.Map;

/**
 * Class to fetch JSON documents
 *
 * This uses a map of {@link URIDownloader} instances to fetch the contents
 * of a URI as an {@link InputStream}, then tries and turns this content into
 * JSON using an {@link ObjectMapper}.
 *
 * Normally, you will never use this class directly.
 *
 * @see DefaultDownloadersDictionary
 * @see SchemaLoader
 */
public final class URIManager
{
    private static final MessageBundle BUNDLE
        = MessageBundles.getBundle(JsonSchemaCoreMessageBundle.class);

    private final Map downloaders;

    private final ObjectReader reader;

    public URIManager()
    {
        this(LoadingConfiguration.byDefault());
    }

    public URIManager(final LoadingConfiguration cfg)
    {
        downloaders = cfg.getDownloaders().entries();
        reader = cfg.getObjectReader();
    }

    /**
     * Get the content at a given URI as a {@link JsonNode}
     *
     * @param uri the URI
     * @return the content
     * @throws NullPointerException provided URI is null
     * @throws ProcessingException scheme is not registered, failed to get
     * content, or content is not JSON
     */
    public JsonNode getContent(final URI uri)
        throws ProcessingException
    {
        BUNDLE.checkNotNull(uri, "jsonRef.nullURI");

        if (!uri.isAbsolute())
            throw new ProcessingException(new ProcessingMessage()
                .setMessage(BUNDLE.getMessage("refProcessing.uriNotAbsolute"))
                .put("uri", uri));

        final String scheme = uri.getScheme();

        final URIDownloader downloader = downloaders.get(scheme);

        if (downloader == null)
            throw new ProcessingException(new ProcessingMessage()
                .setMessage(BUNDLE.getMessage("refProcessing.unhandledScheme"))
                .putArgument("scheme", scheme).putArgument("uri", uri));

        final InputStream in;

        try {
            in = downloader.fetch(uri);
            return reader.readTree(in);
        } catch (JsonProcessingException e) {
            throw new ProcessingException(new ProcessingMessage()
                .setMessage(BUNDLE.getMessage("refProcessing.uriNotJson"))
                .putArgument("uri", uri)
                .put("parsingMessage", e.getOriginalMessage()));
        } catch (IOException e) {
            throw new ProcessingException(new ProcessingMessage()
                .setMessage(BUNDLE.getMessage("refProcessing.uriIOError"))
                .putArgument("uri", uri)
                .put("exceptionMessage", e.getMessage()));
        }
    }
}