Java tutorial
/* * Copyright (C) 2010 The Android Open Source Project * * 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 android.nfc; import android.annotation.UnsupportedAppUsage; import android.content.Intent; import android.net.Uri; import android.os.Parcel; import android.os.Parcelable; import java.nio.BufferUnderflowException; import java.nio.ByteBuffer; import java.nio.charset.StandardCharsets; import java.util.ArrayList; import java.util.Arrays; import java.util.List; import java.util.Locale; /** * Represents an immutable NDEF Record. * <p> * NDEF (NFC Data Exchange Format) is a light-weight binary format, * used to encapsulate typed data. It is specified by the NFC Forum, * for transmission and storage with NFC, however it is transport agnostic. * <p> * NDEF defines messages and records. An NDEF Record contains * typed data, such as MIME-type media, a URI, or a custom * application payload. An NDEF Message is a container for * one or more NDEF Records. * <p> * This class represents logical (complete) NDEF Records, and can not be * used to represent chunked (partial) NDEF Records. However * {@link NdefMessage#NdefMessage(byte[])} can be used to parse a message * containing chunked records, and will return a message with unchunked * (complete) records. * <p> * A logical NDEF Record always contains a 3-bit TNF (Type Name Field) * that provides high level typing for the rest of the record. The * remaining fields are variable length and not always present: * <ul> * <li><em>type</em>: detailed typing for the payload</li> * <li><em>id</em>: identifier meta-data, not commonly used</li> * <li><em>payload</em>: the actual payload</li> * </ul> * <p> * Helpers such as {@link NdefRecord#createUri}, {@link NdefRecord#createMime} * and {@link NdefRecord#createExternal} are included to create well-formatted * NDEF Records with correctly set tnf, type, id and payload fields, please * use these helpers whenever possible. * <p> * Use the constructor {@link #NdefRecord(short, byte[], byte[], byte[])} * if you know what you are doing and what to set the fields individually. * Only basic validation is performed with this constructor, so it is possible * to create records that do not confirm to the strict NFC Forum * specifications. * <p> * The binary representation of an NDEF Record includes additional flags to * indicate location with an NDEF message, provide support for chunking of * NDEF records, and to pack optional fields. This class does not expose * those details. To write an NDEF Record as binary you must first put it * into an {@link NdefMessage}, then call {@link NdefMessage#toByteArray()}. * <p class="note"> * {@link NdefMessage} and {@link NdefRecord} implementations are * always available, even on Android devices that do not have NFC hardware. * <p class="note"> * {@link NdefRecord}s are intended to be immutable (and thread-safe), * however they may contain mutable fields. So take care not to modify * mutable fields passed into constructors, or modify mutable fields * obtained by getter methods, unless such modification is explicitly * marked as safe. * * @see NfcAdapter#ACTION_NDEF_DISCOVERED * @see NdefMessage */ public final class NdefRecord implements Parcelable { /** * Indicates the record is empty.<p> * Type, id and payload fields are empty in a {@literal TNF_EMPTY} record. */ public static final short TNF_EMPTY = 0x00; /** * Indicates the type field contains a well-known RTD type name.<p> * Use this tnf with RTD types such as {@link #RTD_TEXT}, {@link #RTD_URI}. * <p> * The RTD type name format is specified in NFCForum-TS-RTD_1.0. * * @see #RTD_URI * @see #RTD_TEXT * @see #RTD_SMART_POSTER * @see #createUri */ public static final short TNF_WELL_KNOWN = 0x01; /** * Indicates the type field contains a media-type BNF * construct, defined by RFC 2046.<p> * Use this with MIME type names such as {@literal "image/jpeg"}, or * using the helper {@link #createMime}. * * @see #createMime */ public static final short TNF_MIME_MEDIA = 0x02; /** * Indicates the type field contains an absolute-URI * BNF construct defined by RFC 3986.<p> * When creating new records prefer {@link #createUri}, * since it offers more compact URI encoding * ({@literal #RTD_URI} allows compression of common URI prefixes). * * @see #createUri */ public static final short TNF_ABSOLUTE_URI = 0x03; /** * Indicates the type field contains an external type name.<p> * Used to encode custom payloads. When creating new records * use the helper {@link #createExternal}.<p> * The external-type RTD format is specified in NFCForum-TS-RTD_1.0.<p> * <p> * Note this TNF should not be used with RTD_TEXT or RTD_URI constants. * Those are well known RTD constants, not external RTD constants. * * @see #createExternal */ public static final short TNF_EXTERNAL_TYPE = 0x04; /** * Indicates the payload type is unknown.<p> * NFC Forum explains this should be treated similarly to the * "application/octet-stream" MIME type. The payload * type is not explicitly encoded within the record. * <p> * The type field is empty in an {@literal TNF_UNKNOWN} record. */ public static final short TNF_UNKNOWN = 0x05; /** * Indicates the payload is an intermediate or final chunk of a chunked * NDEF Record.<p> * {@literal TNF_UNCHANGED} can not be used with this class * since all {@link NdefRecord}s are already unchunked, however they * may appear in the binary format. */ public static final short TNF_UNCHANGED = 0x06; /** * Reserved TNF type. * <p> * The NFC Forum NDEF Specification v1.0 suggests for NDEF parsers to treat this * value like TNF_UNKNOWN. * @hide */ public static final short TNF_RESERVED = 0x07; /** * RTD Text type. For use with {@literal TNF_WELL_KNOWN}. * @see #TNF_WELL_KNOWN */ public static final byte[] RTD_TEXT = { 0x54 }; // "T" /** * RTD URI type. For use with {@literal TNF_WELL_KNOWN}. * @see #TNF_WELL_KNOWN */ public static final byte[] RTD_URI = { 0x55 }; // "U" /** * RTD Smart Poster type. For use with {@literal TNF_WELL_KNOWN}. * @see #TNF_WELL_KNOWN */ public static final byte[] RTD_SMART_POSTER = { 0x53, 0x70 }; // "Sp" /** * RTD Alternative Carrier type. For use with {@literal TNF_WELL_KNOWN}. * @see #TNF_WELL_KNOWN */ public static final byte[] RTD_ALTERNATIVE_CARRIER = { 0x61, 0x63 }; // "ac" /** * RTD Handover Carrier type. For use with {@literal TNF_WELL_KNOWN}. * @see #TNF_WELL_KNOWN */ public static final byte[] RTD_HANDOVER_CARRIER = { 0x48, 0x63 }; // "Hc" /** * RTD Handover Request type. For use with {@literal TNF_WELL_KNOWN}. * @see #TNF_WELL_KNOWN */ public static final byte[] RTD_HANDOVER_REQUEST = { 0x48, 0x72 }; // "Hr" /** * RTD Handover Select type. For use with {@literal TNF_WELL_KNOWN}. * @see #TNF_WELL_KNOWN */ public static final byte[] RTD_HANDOVER_SELECT = { 0x48, 0x73 }; // "Hs" /** * RTD Android app type. For use with {@literal TNF_EXTERNAL}. * <p> * The payload of a record with type RTD_ANDROID_APP * should be the package name identifying an application. * Multiple RTD_ANDROID_APP records may be included * in a single {@link NdefMessage}. * <p> * Use {@link #createApplicationRecord(String)} to create * RTD_ANDROID_APP records. * @hide */ public static final byte[] RTD_ANDROID_APP = "android.com:pkg".getBytes(); private static final byte FLAG_MB = (byte) 0x80; private static final byte FLAG_ME = (byte) 0x40; private static final byte FLAG_CF = (byte) 0x20; private static final byte FLAG_SR = (byte) 0x10; private static final byte FLAG_IL = (byte) 0x08; /** * NFC Forum "URI Record Type Definition"<p> * This is a mapping of "URI Identifier Codes" to URI string prefixes, * per section 3.2.2 of the NFC Forum URI Record Type Definition document. */ private static final String[] URI_PREFIX_MAP = new String[] { "", // 0x00 "http://www.", // 0x01 "https://www.", // 0x02 "http://", // 0x03 "https://", // 0x04 "tel:", // 0x05 "mailto:", // 0x06 "ftp://anonymous:anonymous@", // 0x07 "ftp://ftp.", // 0x08 "ftps://", // 0x09 "sftp://", // 0x0A "smb://", // 0x0B "nfs://", // 0x0C "ftp://", // 0x0D "dav://", // 0x0E "news:", // 0x0F "telnet://", // 0x10 "imap:", // 0x11 "rtsp://", // 0x12 "urn:", // 0x13 "pop:", // 0x14 "sip:", // 0x15 "sips:", // 0x16 "tftp:", // 0x17 "btspp://", // 0x18 "btl2cap://", // 0x19 "btgoep://", // 0x1A "tcpobex://", // 0x1B "irdaobex://", // 0x1C "file://", // 0x1D "urn:epc:id:", // 0x1E "urn:epc:tag:", // 0x1F "urn:epc:pat:", // 0x20 "urn:epc:raw:", // 0x21 "urn:epc:", // 0x22 "urn:nfc:", // 0x23 }; private static final int MAX_PAYLOAD_SIZE = 10 * (1 << 20); // 10 MB payload limit private static final byte[] EMPTY_BYTE_ARRAY = new byte[0]; private final short mTnf; private final byte[] mType; @UnsupportedAppUsage private final byte[] mId; private final byte[] mPayload; /** * Create a new Android Application Record (AAR). * <p> * This record indicates to other Android devices the package * that should be used to handle the entire NDEF message. * You can embed this record anywhere into your message * to ensure that the intended package receives the message. * <p> * When an Android device dispatches an {@link NdefMessage} * containing one or more Android application records, * the applications contained in those records will be the * preferred target for the {@link NfcAdapter#ACTION_NDEF_DISCOVERED} * intent, in the order in which they appear in the message. * This dispatch behavior was first added to Android in * Ice Cream Sandwich. * <p> * If none of the applications have a are installed on the device, * a Market link will be opened to the first application. * <p> * Note that Android application records do not overrule * applications that have called * {@link NfcAdapter#enableForegroundDispatch}. * * @param packageName Android package name * @return Android application NDEF record */ public static NdefRecord createApplicationRecord(String packageName) { if (packageName == null) throw new NullPointerException("packageName is null"); if (packageName.length() == 0) throw new IllegalArgumentException("packageName is empty"); return new NdefRecord(TNF_EXTERNAL_TYPE, RTD_ANDROID_APP, null, packageName.getBytes(StandardCharsets.UTF_8)); } /** * Create a new NDEF Record containing a URI.<p> * Use this method to encode a URI (or URL) into an NDEF Record.<p> * Uses the well known URI type representation: {@link #TNF_WELL_KNOWN} * and {@link #RTD_URI}. This is the most efficient encoding * of a URI into NDEF.<p> * The uri parameter will be normalized with * {@link Uri#normalizeScheme} to set the scheme to lower case to * follow Android best practices for intent filtering. * However the unchecked exception * {@link IllegalArgumentException} may be thrown if the uri * parameter has serious problems, for example if it is empty, so always * catch this exception if you are passing user-generated data into this * method.<p> * * Reference specification: NFCForum-TS-RTD_URI_1.0 * * @param uri URI to encode. * @return an NDEF Record containing the URI * @throws IllegalArugmentException if the uri is empty or invalid */ public static NdefRecord createUri(Uri uri) { if (uri == null) throw new NullPointerException("uri is null"); uri = uri.normalizeScheme(); String uriString = uri.toString(); if (uriString.length() == 0) throw new IllegalArgumentException("uri is empty"); byte prefix = 0; for (int i = 1; i < URI_PREFIX_MAP.length; i++) { if (uriString.startsWith(URI_PREFIX_MAP[i])) { prefix = (byte) i; uriString = uriString.substring(URI_PREFIX_MAP[i].length()); break; } } byte[] uriBytes = uriString.getBytes(StandardCharsets.UTF_8); byte[] recordBytes = new byte[uriBytes.length + 1]; recordBytes[0] = prefix; System.arraycopy(uriBytes, 0, recordBytes, 1, uriBytes.length); return new NdefRecord(TNF_WELL_KNOWN, RTD_URI, null, recordBytes); } /** * Create a new NDEF Record containing a URI.<p> * Use this method to encode a URI (or URL) into an NDEF Record.<p> * Uses the well known URI type representation: {@link #TNF_WELL_KNOWN} * and {@link #RTD_URI}. This is the most efficient encoding * of a URI into NDEF.<p> * The uriString parameter will be normalized with * {@link Uri#normalizeScheme} to set the scheme to lower case to * follow Android best practices for intent filtering. * However the unchecked exception * {@link IllegalArgumentException} may be thrown if the uriString * parameter has serious problems, for example if it is empty, so always * catch this exception if you are passing user-generated data into this * method.<p> * * Reference specification: NFCForum-TS-RTD_URI_1.0 * * @param uriString string URI to encode. * @return an NDEF Record containing the URI * @throws IllegalArugmentException if the uriString is empty or invalid */ public static NdefRecord createUri(String uriString) { return createUri(Uri.parse(uriString)); } /** * Create a new NDEF Record containing MIME data.<p> * Use this method to encode MIME-typed data into an NDEF Record, * such as "text/plain", or "image/jpeg".<p> * The mimeType parameter will be normalized with * {@link Intent#normalizeMimeType} to follow Android best * practices for intent filtering, for example to force lower-case. * However the unchecked exception * {@link IllegalArgumentException} may be thrown * if the mimeType parameter has serious problems, * for example if it is empty, so always catch this * exception if you are passing user-generated data into this method. * <p> * For efficiency, This method might not make an internal copy of the * mimeData byte array, so take care not * to modify the mimeData byte array while still using the returned * NdefRecord. * * @param mimeType a valid MIME type * @param mimeData MIME data as bytes * @return an NDEF Record containing the MIME-typed data * @throws IllegalArugmentException if the mimeType is empty or invalid * */ public static NdefRecord createMime(String mimeType, byte[] mimeData) { if (mimeType == null) throw new NullPointerException("mimeType is null"); // We only do basic MIME type validation: trying to follow the // RFCs strictly only ends in tears, since there are lots of MIME // types in common use that are not strictly valid as per RFC rules mimeType = Intent.normalizeMimeType(mimeType); if (mimeType.length() == 0) throw new IllegalArgumentException("mimeType is empty"); int slashIndex = mimeType.indexOf('/'); if (slashIndex == 0) throw new IllegalArgumentException("mimeType must have major type"); if (slashIndex == mimeType.length() - 1) { throw new IllegalArgumentException("mimeType must have minor type"); } // missing '/' is allowed // MIME RFCs suggest ASCII encoding for content-type byte[] typeBytes = mimeType.getBytes(StandardCharsets.US_ASCII); return new NdefRecord(TNF_MIME_MEDIA, typeBytes, null, mimeData); } /** * Create a new NDEF Record containing external (application-specific) data.<p> * Use this method to encode application specific data into an NDEF Record. * The data is typed by a domain name (usually your Android package name) and * a domain-specific type. This data is packaged into a "NFC Forum External * Type" NDEF Record.<p> * NFC Forum requires that the domain and type used in an external record * are treated as case insensitive, however Android intent filtering is * always case sensitive. So this method will force the domain and type to * lower-case before creating the NDEF Record.<p> * The unchecked exception {@link IllegalArgumentException} will be thrown * if the domain and type have serious problems, for example if either field * is empty, so always catch this * exception if you are passing user-generated data into this method.<p> * There are no such restrictions on the payload data.<p> * For efficiency, This method might not make an internal copy of the * data byte array, so take care not * to modify the data byte array while still using the returned * NdefRecord. * * Reference specification: NFCForum-TS-RTD_1.0 * @param domain domain-name of issuing organization * @param type domain-specific type of data * @param data payload as bytes * @throws IllegalArugmentException if either domain or type are empty or invalid */ public static NdefRecord createExternal(String domain, String type, byte[] data) { if (domain == null) throw new NullPointerException("domain is null"); if (type == null) throw new NullPointerException("type is null"); domain = domain.trim().toLowerCase(Locale.ROOT); type = type.trim().toLowerCase(Locale.ROOT); if (domain.length() == 0) throw new IllegalArgumentException("domain is empty"); if (type.length() == 0) throw new IllegalArgumentException("type is empty"); byte[] byteDomain = domain.getBytes(StandardCharsets.UTF_8); byte[] byteType = type.getBytes(StandardCharsets.UTF_8); byte[] b = new byte[byteDomain.length + 1 + byteType.length]; System.arraycopy(byteDomain, 0, b, 0, byteDomain.length); b[byteDomain.length] = ':'; System.arraycopy(byteType, 0, b, byteDomain.length + 1, byteType.length); return new NdefRecord(TNF_EXTERNAL_TYPE, b, null, data); } /** * Create a new NDEF record containing UTF-8 text data.<p> * * The caller can either specify the language code for the provided text, * or otherwise the language code corresponding to the current default * locale will be used. * * Reference specification: NFCForum-TS-RTD_Text_1.0 * @param languageCode The languageCode for the record. If locale is empty or null, * the language code of the current default locale will be used. * @param text The text to be encoded in the record. Will be represented in UTF-8 format. * @throws IllegalArgumentException if text is null */ public static NdefRecord createTextRecord(String languageCode, String text) { if (text == null) throw new NullPointerException("text is null"); byte[] textBytes = text.getBytes(StandardCharsets.UTF_8); byte[] languageCodeBytes = null; if (languageCode != null && !languageCode.isEmpty()) { languageCodeBytes = languageCode.getBytes(StandardCharsets.US_ASCII); } else { languageCodeBytes = Locale.getDefault().getLanguage().getBytes(StandardCharsets.US_ASCII); } // We only have 6 bits to indicate ISO/IANA language code. if (languageCodeBytes.length >= 64) { throw new IllegalArgumentException("language code is too long, must be <64 bytes."); } ByteBuffer buffer = ByteBuffer.allocate(1 + languageCodeBytes.length + textBytes.length); byte status = (byte) (languageCodeBytes.length & 0xFF); buffer.put(status); buffer.put(languageCodeBytes); buffer.put(textBytes); return new NdefRecord(TNF_WELL_KNOWN, RTD_TEXT, null, buffer.array()); } /** * Construct an NDEF Record from its component fields.<p> * Recommend to use helpers such as {#createUri} or * {{@link #createExternal} where possible, since they perform * stricter validation that the record is correctly formatted * as per NDEF specifications. However if you know what you are * doing then this constructor offers the most flexibility.<p> * An {@link NdefRecord} represents a logical (complete) * record, and cannot represent NDEF Record chunks.<p> * Basic validation of the tnf, type, id and payload is performed * as per the following rules: * <ul> * <li>The tnf paramter must be a 3-bit value.</li> * <li>Records with a tnf of {@link #TNF_EMPTY} cannot have a type, * id or payload.</li> * <li>Records with a tnf of {@link #TNF_UNKNOWN} or {@literal 0x07} * cannot have a type.</li> * <li>Records with a tnf of {@link #TNF_UNCHANGED} are not allowed * since this class only represents complete (unchunked) records.</li> * </ul> * This minimal validation is specified by * NFCForum-TS-NDEF_1.0 section 3.2.6 (Type Name Format).<p> * If any of the above validation * steps fail then {@link IllegalArgumentException} is thrown.<p> * Deep inspection of the type, id and payload fields is not * performed, so it is possible to create NDEF Records * that conform to section 3.2.6 * but fail other more strict NDEF specification requirements. For * example, the payload may be invalid given the tnf and type. * <p> * To omit a type, id or payload field, set the parameter to an * empty byte array or null. * * @param tnf a 3-bit TNF constant * @param type byte array, containing zero to 255 bytes, or null * @param id byte array, containing zero to 255 bytes, or null * @param payload byte array, containing zero to (2 ** 32 - 1) bytes, * or null * @throws IllegalArugmentException if a valid record cannot be created */ public NdefRecord(short tnf, byte[] type, byte[] id, byte[] payload) { /* convert nulls */ if (type == null) type = EMPTY_BYTE_ARRAY; if (id == null) id = EMPTY_BYTE_ARRAY; if (payload == null) payload = EMPTY_BYTE_ARRAY; String message = validateTnf(tnf, type, id, payload); if (message != null) { throw new IllegalArgumentException(message); } mTnf = tnf; mType = type; mId = id; mPayload = payload; } /** * Construct an NDEF Record from raw bytes.<p> * This method is deprecated, use {@link NdefMessage#NdefMessage(byte[])} * instead. This is because it does not make sense to parse a record: * the NDEF binary format is only defined for a message, and the * record flags MB and ME do not make sense outside of the context of * an entire message.<p> * This implementation will attempt to parse a single record by ignoring * the MB and ME flags, and otherwise following the rules of * {@link NdefMessage#NdefMessage(byte[])}.<p> * * @param data raw bytes to parse * @throws FormatException if the data cannot be parsed into a valid record * @deprecated use {@link NdefMessage#NdefMessage(byte[])} instead. */ @Deprecated public NdefRecord(byte[] data) throws FormatException { ByteBuffer buffer = ByteBuffer.wrap(data); NdefRecord[] rs = parse(buffer, true); if (buffer.remaining() > 0) { throw new FormatException("data too long"); } mTnf = rs[0].mTnf; mType = rs[0].mType; mId = rs[0].mId; mPayload = rs[0].mPayload; } /** * Returns the 3-bit TNF. * <p> * TNF is the top-level type. */ public short getTnf() { return mTnf; } /** * Returns the variable length Type field. * <p> * This should be used in conjunction with the TNF field to determine the * payload format. * <p> * Returns an empty byte array if this record * does not have a type field. */ public byte[] getType() { return mType.clone(); } /** * Returns the variable length ID. * <p> * Returns an empty byte array if this record * does not have an id field. */ public byte[] getId() { return mId.clone(); } /** * Returns the variable length payload. * <p> * Returns an empty byte array if this record * does not have a payload field. */ public byte[] getPayload() { return mPayload.clone(); } /** * Return this NDEF Record as a byte array.<p> * This method is deprecated, use {@link NdefMessage#toByteArray} * instead. This is because the NDEF binary format is not defined for * a record outside of the context of a message: the MB and ME flags * cannot be set without knowing the location inside a message.<p> * This implementation will attempt to serialize a single record by * always setting the MB and ME flags (in other words, assume this * is a single-record NDEF Message).<p> * * @deprecated use {@link NdefMessage#toByteArray()} instead */ @Deprecated public byte[] toByteArray() { ByteBuffer buffer = ByteBuffer.allocate(getByteLength()); writeToByteBuffer(buffer, true, true); return buffer.array(); } /** * Map this record to a MIME type, or return null if it cannot be mapped.<p> * Currently this method considers all {@link #TNF_MIME_MEDIA} records to * be MIME records, as well as some {@link #TNF_WELL_KNOWN} records such as * {@link #RTD_TEXT}. If this is a MIME record then the MIME type as string * is returned, otherwise null is returned.<p> * This method does not perform validation that the MIME type is * actually valid. It always attempts to * return a string containing the type if this is a MIME record.<p> * The returned MIME type will by normalized to lower-case using * {@link Intent#normalizeMimeType}.<p> * The MIME payload can be obtained using {@link #getPayload}. * * @return MIME type as a string, or null if this is not a MIME record */ public String toMimeType() { switch (mTnf) { case NdefRecord.TNF_WELL_KNOWN: if (Arrays.equals(mType, NdefRecord.RTD_TEXT)) { return "text/plain"; } break; case NdefRecord.TNF_MIME_MEDIA: String mimeType = new String(mType, StandardCharsets.US_ASCII); return Intent.normalizeMimeType(mimeType); } return null; } /** * Map this record to a URI, or return null if it cannot be mapped.<p> * Currently this method considers the following to be URI records: * <ul> * <li>{@link #TNF_ABSOLUTE_URI} records.</li> * <li>{@link #TNF_WELL_KNOWN} with a type of {@link #RTD_URI}.</li> * <li>{@link #TNF_WELL_KNOWN} with a type of {@link #RTD_SMART_POSTER} * and containing a URI record in the NDEF message nested in the payload. * </li> * <li>{@link #TNF_EXTERNAL_TYPE} records.</li> * </ul> * If this is not a URI record by the above rules, then null is returned.<p> * This method does not perform validation that the URI is * actually valid: it always attempts to create and return a URI if * this record appears to be a URI record by the above rules.<p> * The returned URI will be normalized to have a lower case scheme * using {@link Uri#normalizeScheme}.<p> * * @return URI, or null if this is not a URI record */ public Uri toUri() { return toUri(false); } private Uri toUri(boolean inSmartPoster) { switch (mTnf) { case TNF_WELL_KNOWN: if (Arrays.equals(mType, RTD_SMART_POSTER) && !inSmartPoster) { try { // check payload for a nested NDEF Message containing a URI NdefMessage nestedMessage = new NdefMessage(mPayload); for (NdefRecord nestedRecord : nestedMessage.getRecords()) { Uri uri = nestedRecord.toUri(true); if (uri != null) { return uri; } } } catch (FormatException e) { } } else if (Arrays.equals(mType, RTD_URI)) { Uri wktUri = parseWktUri(); return (wktUri != null ? wktUri.normalizeScheme() : null); } break; case TNF_ABSOLUTE_URI: Uri uri = Uri.parse(new String(mType, StandardCharsets.UTF_8)); return uri.normalizeScheme(); case TNF_EXTERNAL_TYPE: if (inSmartPoster) { break; } return Uri.parse("vnd.android.nfc://ext/" + new String(mType, StandardCharsets.US_ASCII)); } return null; } /** * Return complete URI of {@link #TNF_WELL_KNOWN}, {@link #RTD_URI} records. * @return complete URI, or null if invalid */ private Uri parseWktUri() { if (mPayload.length < 2) { return null; } // payload[0] contains the URI Identifier Code, as per // NFC Forum "URI Record Type Definition" section 3.2.2. int prefixIndex = (mPayload[0] & (byte) 0xFF); if (prefixIndex < 0 || prefixIndex >= URI_PREFIX_MAP.length) { return null; } String prefix = URI_PREFIX_MAP[prefixIndex]; String suffix = new String(Arrays.copyOfRange(mPayload, 1, mPayload.length), StandardCharsets.UTF_8); return Uri.parse(prefix + suffix); } /** * Main record parsing method.<p> * Expects NdefMessage to begin immediately, allows trailing data.<p> * Currently has strict validation of all fields as per NDEF 1.0 * specification section 2.5. We will attempt to keep this as strict as * possible to encourage well-formatted NDEF.<p> * Always returns 1 or more NdefRecord's, or throws FormatException. * * @param buffer ByteBuffer to read from * @param ignoreMbMe ignore MB and ME flags, and read only 1 complete record * @return one or more records * @throws FormatException on any parsing error */ static NdefRecord[] parse(ByteBuffer buffer, boolean ignoreMbMe) throws FormatException { List<NdefRecord> records = new ArrayList<NdefRecord>(); try { byte[] type = null; byte[] id = null; byte[] payload = null; ArrayList<byte[]> chunks = new ArrayList<byte[]>(); boolean inChunk = false; short chunkTnf = -1; boolean me = false; while (!me) { byte flag = buffer.get(); boolean mb = (flag & NdefRecord.FLAG_MB) != 0; me = (flag & NdefRecord.FLAG_ME) != 0; boolean cf = (flag & NdefRecord.FLAG_CF) != 0; boolean sr = (flag & NdefRecord.FLAG_SR) != 0; boolean il = (flag & NdefRecord.FLAG_IL) != 0; short tnf = (short) (flag & 0x07); if (!mb && records.size() == 0 && !inChunk && !ignoreMbMe) { throw new FormatException("expected MB flag"); } else if (mb && (records.size() != 0 || inChunk) && !ignoreMbMe) { throw new FormatException("unexpected MB flag"); } else if (inChunk && il) { throw new FormatException("unexpected IL flag in non-leading chunk"); } else if (cf && me) { throw new FormatException("unexpected ME flag in non-trailing chunk"); } else if (inChunk && tnf != NdefRecord.TNF_UNCHANGED) { throw new FormatException("expected TNF_UNCHANGED in non-leading chunk"); } else if (!inChunk && tnf == NdefRecord.TNF_UNCHANGED) { throw new FormatException("" + "unexpected TNF_UNCHANGED in first chunk or unchunked record"); } int typeLength = buffer.get() & 0xFF; long payloadLength = sr ? (buffer.get() & 0xFF) : (buffer.getInt() & 0xFFFFFFFFL); int idLength = il ? (buffer.get() & 0xFF) : 0; if (inChunk && typeLength != 0) { throw new FormatException("expected zero-length type in non-leading chunk"); } if (!inChunk) { type = (typeLength > 0 ? new byte[typeLength] : EMPTY_BYTE_ARRAY); id = (idLength > 0 ? new byte[idLength] : EMPTY_BYTE_ARRAY); buffer.get(type); buffer.get(id); } ensureSanePayloadSize(payloadLength); payload = (payloadLength > 0 ? new byte[(int) payloadLength] : EMPTY_BYTE_ARRAY); buffer.get(payload); if (cf && !inChunk) { // first chunk if (typeLength == 0 && tnf != NdefRecord.TNF_UNKNOWN) { throw new FormatException("expected non-zero type length in first chunk"); } chunks.clear(); chunkTnf = tnf; } if (cf || inChunk) { // any chunk chunks.add(payload); } if (!cf && inChunk) { // last chunk, flatten the payload payloadLength = 0; for (byte[] p : chunks) { payloadLength += p.length; } ensureSanePayloadSize(payloadLength); payload = new byte[(int) payloadLength]; int i = 0; for (byte[] p : chunks) { System.arraycopy(p, 0, payload, i, p.length); i += p.length; } tnf = chunkTnf; } if (cf) { // more chunks to come inChunk = true; continue; } else { inChunk = false; } String error = validateTnf(tnf, type, id, payload); if (error != null) { throw new FormatException(error); } records.add(new NdefRecord(tnf, type, id, payload)); if (ignoreMbMe) { // for parsing a single NdefRecord break; } } } catch (BufferUnderflowException e) { throw new FormatException("expected more data", e); } return records.toArray(new NdefRecord[records.size()]); } private static void ensureSanePayloadSize(long size) throws FormatException { if (size > MAX_PAYLOAD_SIZE) { throw new FormatException("payload above max limit: " + size + " > " + MAX_PAYLOAD_SIZE); } } /** * Perform simple validation that the tnf is valid.<p> * Validates the requirements of NFCForum-TS-NDEF_1.0 section * 3.2.6 (Type Name Format). This just validates that the tnf * is valid, and that the relevant type, id and payload * fields are present (or empty) for this tnf. It does not * perform any deep inspection of the type, id and payload fields.<p> * Also does not allow TNF_UNCHANGED since this class is only used * to present logical (unchunked) records. * * @return null if valid, or a string error if invalid. */ static String validateTnf(short tnf, byte[] type, byte[] id, byte[] payload) { switch (tnf) { case TNF_EMPTY: if (type.length != 0 || id.length != 0 || payload.length != 0) { return "unexpected data in TNF_EMPTY record"; } return null; case TNF_WELL_KNOWN: case TNF_MIME_MEDIA: case TNF_ABSOLUTE_URI: case TNF_EXTERNAL_TYPE: return null; case TNF_UNKNOWN: case TNF_RESERVED: if (type.length != 0) { return "unexpected type field in TNF_UNKNOWN or TNF_RESERVEd record"; } return null; case TNF_UNCHANGED: return "unexpected TNF_UNCHANGED in first chunk or logical record"; default: return String.format("unexpected tnf value: 0x%02x", tnf); } } /** * Serialize record for network transmission.<p> * Uses specified MB and ME flags.<p> * Does not chunk records. */ void writeToByteBuffer(ByteBuffer buffer, boolean mb, boolean me) { boolean sr = mPayload.length < 256; boolean il = mTnf == TNF_EMPTY ? true : mId.length > 0; byte flags = (byte) ((mb ? FLAG_MB : 0) | (me ? FLAG_ME : 0) | (sr ? FLAG_SR : 0) | (il ? FLAG_IL : 0) | mTnf); buffer.put(flags); buffer.put((byte) mType.length); if (sr) { buffer.put((byte) mPayload.length); } else { buffer.putInt(mPayload.length); } if (il) { buffer.put((byte) mId.length); } buffer.put(mType); buffer.put(mId); buffer.put(mPayload); } /** * Get byte length of serialized record. */ int getByteLength() { int length = 3 + mType.length + mId.length + mPayload.length; boolean sr = mPayload.length < 256; boolean il = mTnf == TNF_EMPTY ? true : mId.length > 0; if (!sr) length += 3; if (il) length += 1; return length; } @Override public int describeContents() { return 0; } @Override public void writeToParcel(Parcel dest, int flags) { dest.writeInt(mTnf); dest.writeInt(mType.length); dest.writeByteArray(mType); dest.writeInt(mId.length); dest.writeByteArray(mId); dest.writeInt(mPayload.length); dest.writeByteArray(mPayload); } public static final Parcelable.Creator<NdefRecord> CREATOR = new Parcelable.Creator<NdefRecord>() { @Override public NdefRecord createFromParcel(Parcel in) { short tnf = (short) in.readInt(); int typeLength = in.readInt(); byte[] type = new byte[typeLength]; in.readByteArray(type); int idLength = in.readInt(); byte[] id = new byte[idLength]; in.readByteArray(id); int payloadLength = in.readInt(); byte[] payload = new byte[payloadLength]; in.readByteArray(payload); return new NdefRecord(tnf, type, id, payload); } @Override public NdefRecord[] newArray(int size) { return new NdefRecord[size]; } }; @Override public int hashCode() { final int prime = 31; int result = 1; result = prime * result + Arrays.hashCode(mId); result = prime * result + Arrays.hashCode(mPayload); result = prime * result + mTnf; result = prime * result + Arrays.hashCode(mType); return result; } /** * Returns true if the specified NDEF Record contains * identical tnf, type, id and payload fields. */ @Override public boolean equals(Object obj) { if (this == obj) return true; if (obj == null) return false; if (getClass() != obj.getClass()) return false; NdefRecord other = (NdefRecord) obj; if (!Arrays.equals(mId, other.mId)) return false; if (!Arrays.equals(mPayload, other.mPayload)) return false; if (mTnf != other.mTnf) return false; return Arrays.equals(mType, other.mType); } @Override public String toString() { StringBuilder b = new StringBuilder(String.format("NdefRecord tnf=%X", mTnf)); if (mType.length > 0) b.append(" type=").append(bytesToString(mType)); if (mId.length > 0) b.append(" id=").append(bytesToString(mId)); if (mPayload.length > 0) b.append(" payload=").append(bytesToString(mPayload)); return b.toString(); } private static StringBuilder bytesToString(byte[] bs) { StringBuilder s = new StringBuilder(); for (byte b : bs) { s.append(String.format("%02X", b)); } return s; } }