com.sixestates.http.HttpRequestFormResolver Maven / Gradle / Ivy

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A Java SDK for communicating with the 6Estates Intelligent Document Processing(IDP) Platform
There is a newer version: 8.2.3
package com.sixestates.http;

import com.sun.net.httpserver.Headers;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;

public class HttpRequestFormResolver {

    private static final int PARAM_INDEX = "Content-Disposition: form-data; ".length();

    public static List resolveForm(Headers headers, byte[] body) throws IOException {
        String contentType = headers.getFirst("Content-type");
        String boundary = contentType.substring(contentType.indexOf("=") + 1);
        boundary = "--" + boundary; //size 52
        byte[] boundaryBytes = boundary.getBytes(StandardCharsets.UTF_8);

        List paramItems = new LinkedList<>();
        List boundaryIndex = boundaryIndex(body, boundaryBytes);
        int paramSize = boundaryIndex.size() - 1;

        int boundaryLen = boundaryBytes.length;
        byte[] sep = "\r\n".getBytes(StandardCharsets.UTF_8);
        for (int i = 0; i < paramSize; i++) {
            ParamItem paramItem = resolveParam(body, boundaryIndex.get(i)+boundaryLen+2, boundaryIndex.get(i+1), sep);
            paramItems.add(paramItem);
        }

        return paramItems;
    }

    /**
     * Single parameter resolution
     */
    private static ParamItem resolveParam(byte[] body, int start, int end, byte[] sep) {
        int count = 0;
        int cursor = start;
        ParamItem paramItem = null;
        for (int i = start; i < end; i++) {
            for (int j = 0; j < 2; j++) {
                if (body[i + j] == sep[j]) {
                    count++;
                } else {
                    break;
                }
            }

            if (count == 2) {
                byte[] line = new byte[i-cursor];
                System.arraycopy(body, cursor, line, 0,i-cursor);

                // Http post key value separator: \r\n
                if (isLineBlank(line)) {
                    cursor = i+2;
                    if (paramItem == null) {
                        return null;
                    }
                    if (paramItem.getType().equals("text")) {
                        byte[] val = new byte[end - cursor-2];
                        System.arraycopy(body, cursor, val, 0, end-cursor-2);
                        paramItem.setVal(new String(val));
                    } else {
                        paramItem.setStartIndex(cursor);
                        paramItem.setEndIndex(end);
                    }
                    break;
                } else {
                    String lineStr = new String(line);
                    if (lineStr.startsWith("Content-Disposition: form-data; ")) {
                        paramItem = resolveParam(lineStr);
                    }
                    cursor = i;
                }
                i++;
            }
            count = 0;
        }
        return paramItem;
    }

    private static ParamItem resolveParam(String lineStr){
        lineStr = lineStr.substring(PARAM_INDEX);
        String[] kVs = lineStr.split(";");
        ParamItem paramItem = new ParamItem();
        paramItem.setType("text");
        for (String kV : kVs) {
            String[] k_v = kV.trim().split("=");
            if ("name".equals(k_v[0])) {
                paramItem.setName(k_v[1].replace("\"", ""));
            } else if ("filename".equals(k_v[0])) {
                paramItem.setFilename(k_v[1].replace("\"", ""));
                paramItem.setType("file");
            }
        }
        return paramItem;
    }

    private static boolean isLineBlank(byte[] line){
        if (line.length == 0) {
            return true;
        }

        byte[] sep = "\r\n".getBytes(StandardCharsets.UTF_8);
        if (line.length == 2) {
            if (line[0] ==  sep[0] && line[1] == sep[1]) {
                return true;
            }
        }
        return false;
    }

    /**
     * Calculate index
     */
    private static List boundaryIndex(byte[] body, byte[] boundary){
        int count = 0;
        List list = new ArrayList<>();
        int length = body.length;
        int boundaryLen = boundary.length;

        for (int i = 0; i < length; i++) {
            for (int j = 0; j < boundaryLen; j++) {
                if (i + j == length) {
                    return list;
                }
                if (body[i + j] == boundary[j]) {
                    count++;
                } else {
                    break;
                }
            }
            if (count == boundaryLen) {
                list.add(i);
                i += boundaryLen - 1;
            }
            count = 0;
        }

        return list;
    }

    public static class ParamItem {
        private String type;
        private String name;
        private String filename;
        private String val;
        private int startIndex;
        private int endIndex;

        public String getType() {
            return type;
        }

        public void setType(String type) {
            this.type = type;
        }

        public String getName() {
            return name;
        }

        public void setName(String name) {
            this.name = name;
        }

        public String getFilename() {
            return filename;
        }

        public void setFilename(String filename) {
            this.filename = filename;
        }

        public String getVal() {
            return val;
        }

        public void setVal(String val) {
            this.val = val;
        }

        public int getStartIndex() {
            return startIndex;
        }

        public void setStartIndex(int startIndex) {
            this.startIndex = startIndex;
        }

        public int getEndIndex() {
            return endIndex;
        }

        public void setEndIndex(int endIndex) {
            this.endIndex = endIndex;
        }

        @Override
        public String toString() {
            return "ParamItem{" +
                    "type='" + type + '\'' +
                    ", name='" + name + '\'' +
                    ", filename='" + filename + '\'' +
                    ", val='" + val + '\'' +
                    ", startIndex=" + startIndex +
                    ", endIndex=" + endIndex +
                    '}';
        }
    }
}