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/*
* ContentDispositionParser.java February 2007
*
* Copyright (C) 2007, Niall Gallagher
*
* 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 org.simpleframework.http.parse;
import org.simpleframework.http.ContentDisposition;
import org.simpleframework.util.parse.ParseBuffer;
import org.simpleframework.util.parse.Parser;
/**
* The ContentDispositionParser object is used to represent
* a parser used to parse the Content-Disposition header. Its used when
* there is a multipart form upload to the server and allows the
* server to determine the individual part types.
*
* @author Niall Gallagher
*/
public class ContentDispositionParser extends Parser implements ContentDisposition {
/**
* This is the buffer used to acquire values from the header.
*/
private ParseBuffer skip;
/**
* This is used to capture the name of the file if it is provided.
*/
private ParseBuffer file;
/**
* This is used to capture the name of the part if it is provided.
*/
private ParseBuffer name;
/**
* This is used to determine if the disposition is a file or form.
*/
private boolean form;
/**
* Constructor for the ContentDispositionParser object.
* This is used to create a parser that can parse a disposition
* header which is typically sent as part of a multipart upload. It
* can be used to determine the type of the upload.
*/
public ContentDispositionParser() {
this.file = new ParseBuffer();
this.name = new ParseBuffer();
this.skip = new ParseBuffer();
}
/**
* Constructor for the ContentDispositionParser object.
* This is used to create a parser that can parse a disposition header
* which is typically sent as part of a multipart upload. It can
* be used to determine the type of the upload.
*
* @param text this is the header value that is to be parsed
*/
public ContentDispositionParser(String text) {
this();
parse(text);
}
/**
* This method is used to acquire the file name of the part. This
* is used when the part represents a text parameter rather than
* a file. However, this can also be used with a file part.
*
* @return this returns the file name of the associated part
*/
public String getFileName() {
return file.toString();
}
/**
* This method is used to acquire the name of the part. Typically
* this is used when the part represents a text parameter rather
* than a file. However, this can also be used with a file part.
*
* @return this returns the name of the associated part
*/
public String getName() {
return name.toString();
}
/**
* This method is used to determine the type of a part. Typically
* a part is either a text parameter or a file. If this is true
* then the content represented by the associated part is a file.
*
* @return this returns true if the associated part is a file
*/
public boolean isFile() {
return !form || file.length() > 0;
}
/**
* This will initialize the Parser when it is ready
* to parse a new String. This will reset the
* parser to a ready state. This method is invoked by the parser
* before the parse method is invoked, it is used to pack the
* contents of the header and clear any previous tokens used.
*/
protected void init() {
if(count > 0) {
pack();
}
clear();
}
/**
* This is used to clear all previously collected tokens. This
* allows the parser to be reused when there are multiple source
* strings to be parsed. Clearing of the tokens is performed
* when the parser is initialized.
*/
protected void clear() {
file.clear();
name.clear();
form = false;
off = 0;
}
/**
* This is the method that should be implemented to read the
* buffer. This method will extract the type from the header and
* the tries to extract the optional parameters if they are in
* the header. The optional parts are the file name and name.
*/
protected void parse() {
type();
parameters();
}
/**
* This is used to remove all whitespace characters from the
* String excluding the whitespace within literals.
* The definition of a literal can be found in RFC 2616.
*
* The definition of a literal for RFC 2616 is anything between 2
* quotes but excuding quotes that are prefixed with the backward
* slash character.
*/
private void pack() {
char old = buf[0];
int len = count;
int seek = 0;
int pos = 0;
while(seek < len){
char ch = buf[seek++];
if(ch == '"' && old != '\\'){ /* qd-text*/
buf[pos++] = ch;
while(seek < len){
old = buf[seek-1];
ch = buf[seek++];
buf[pos++] = ch;
if(ch =='"'&& old!='\\'){ /*qd-text*/
break;
}
}
}else if(!space(ch)){
old = buf[seek - 1];
buf[pos++] = old;
}
}
count = pos;
}
/**
* This is used to determine the type of the disposition header. This
* will allow the parser to determine it the header represents form
* data or a file upload. Once it determines the type of the upload
* header it sets an internal flag which can be used.
*/
private void type() {
if(skip("form-data")) {
form = true;
} else if(skip("file")) {
form = false;
}
}
/**
* This will read the parameters from the header value. This will search
* for the filename parameter within the set of parameters
* which are given to the type. The filename param and the
* the name are tokenized by this method.
*/
private void parameters(){
while(skip(";")){
if(skip("filename=")){
value(file);
} else {
if(skip("name=")) {
value(name);
} else {
parameter();
}
}
}
}
/**
* This will read the parameters from the header value. This will search
* for the filename parameter within the set of parameters
* which are given to the type. The filename param and the
* the name are tokenized by this method.
*/
private void parameter() {
name();
off++;
value(skip);
}
/**
* This will simply read all characters from the buffer before the first '='
* character. This represents a parameter name (see RFC 2616 for token). The
* parameter name is not buffered it is simply read from the buffer. This will
* not cause an IndexOutOfBoundsException as each offset
* is checked before it is acccessed.
*/
private void name(){
while(off < count){
if(buf[off] =='='){
break;
}
off++;
}
}
/**
* This is used to read a parameters value from the buf. This will read all
* char's upto but excluding the first terminal char
* encountered from the off within the buf, or if the value is a literal
* it will read a literal from the buffer (literal is any data between
* quotes except if the quote is prefixed with a backward slash character).
*
* @param value this is the parse buffer to append the value to
*/
private void value(ParseBuffer value) {
if(quote(buf[off])) {
char quote = buf[off];
for(off++; off < count;) {
if(quote == buf[off]) {
if(buf[++off - 2] != '\\') {
break;
}
}
value.append(buf[off++]);
}
} else {
while(off < count) {
if(buf[off] == ';') {
break;
}
value.append(buf[off]);
off++;
}
}
}
/**
* This method is used to determine if the specified character is a quote
* character. The quote character is typically used as a boundary for the
* values within the header. This accepts a single or double quote.
*
* @param ch the character to determine if it is a quotation
*
* @return true if the character provided is a quotation character
*/
private boolean quote(char ch) {
return ch == '\'' || ch == '"';
}
}