Revision 6269
Added by ben leinfelder almost 13 years ago
| CNResourceHandler.java | ||
|---|---|---|
| 31 | 31 |
import java.io.PrintWriter; |
| 32 | 32 |
import java.util.Date; |
| 33 | 33 |
import java.util.Hashtable; |
| 34 |
import java.util.Iterator; |
|
| 35 |
import java.util.List; |
|
| 36 | 34 |
import java.util.Map; |
| 37 | 35 |
import java.util.Timer; |
| 38 | 36 |
|
| ... | ... | |
| 40 | 38 |
import javax.servlet.http.HttpServletRequest; |
| 41 | 39 |
import javax.servlet.http.HttpServletResponse; |
| 42 | 40 |
|
| 41 |
import org.apache.commons.fileupload.FileUploadException; |
|
| 43 | 42 |
import org.apache.commons.io.IOUtils; |
| 44 | 43 |
import org.apache.log4j.Logger; |
| 45 | 44 |
import org.dataone.client.ObjectFormatCache; |
| 46 | 45 |
import org.dataone.client.auth.CertificateManager; |
| 47 |
import org.dataone.mimemultipart.MultipartRequest; |
|
| 48 |
import org.dataone.mimemultipart.MultipartRequestResolver; |
|
| 49 | 46 |
import org.dataone.service.exceptions.BaseException; |
| 50 | 47 |
import org.dataone.service.exceptions.IdentifierNotUnique; |
| 51 | 48 |
import org.dataone.service.exceptions.InsufficientResources; |
| ... | ... | |
| 69 | 66 |
import org.dataone.service.types.Permission; |
| 70 | 67 |
import org.dataone.service.types.Subject; |
| 71 | 68 |
import org.dataone.service.types.SystemMetadata; |
| 72 |
import org.jibx.runtime.BindingDirectory; |
|
| 73 |
import org.jibx.runtime.IBindingFactory; |
|
| 74 |
import org.jibx.runtime.IUnmarshallingContext; |
|
| 75 | 69 |
import org.jibx.runtime.JiBXException; |
| 76 | 70 |
|
| 77 |
import edu.ucsb.nceas.metacat.IdentifierManager; |
|
| 78 | 71 |
import edu.ucsb.nceas.metacat.MetacatHandler; |
| 79 | 72 |
import edu.ucsb.nceas.metacat.dataone.CNodeService; |
| 80 | 73 |
|
| ... | ... | |
| 585 | 578 |
* |
| 586 | 579 |
* @param guid - ID of data object to be inserted or updated. If action is update, the pid |
| 587 | 580 |
* is the existing pid. If insert, the pid is the new one |
| 588 |
* @throws IOException |
|
| 581 |
* @throws InvalidRequest |
|
| 582 |
* @throws ServiceFailure |
|
| 583 |
* @throws IdentifierNotUnique |
|
| 584 |
* @throws JiBXException |
|
| 585 |
* @throws NotImplemented |
|
| 586 |
* @throws InvalidSystemMetadata |
|
| 587 |
* @throws InsufficientResources |
|
| 588 |
* @throws UnsupportedType |
|
| 589 |
* @throws NotAuthorized |
|
| 590 |
* @throws InvalidToken |
|
| 591 |
* @throws IOException |
|
| 589 | 592 |
*/ |
| 590 |
protected void putObject(String pid, String action) {
|
|
| 591 |
logMetacat.debug("putObject with pid " + pid);
|
|
| 593 |
protected void putObject(String pid, String action) throws ServiceFailure, InvalidRequest, IdentifierNotUnique, JiBXException, InvalidToken, NotAuthorized, UnsupportedType, InsufficientResources, InvalidSystemMetadata, NotImplemented, IOException {
|
|
| 592 | 594 |
logMetacat.debug("Entering putObject: " + pid + "/" + action);
|
| 593 |
OutputStream out = null; |
|
| 594 |
try {
|
|
| 595 |
out = response.getOutputStream(); |
|
| 596 |
response.setStatus(200); |
|
| 597 |
response.setContentType("text/xml");
|
|
| 598 |
} catch (IOException e1) {
|
|
| 599 |
logMetacat.error("Could not get the output stream for writing in putObject");
|
|
| 600 |
} |
|
| 601 |
try {
|
|
| 602 |
|
|
| 603 |
// Read the incoming data from its Mime Multipart encoding |
|
| 604 |
logMetacat.debug("Disassembling MIME multipart form");
|
|
| 605 |
InputStream object = null; |
|
| 606 |
InputStream sysmeta = null; |
|
| 607 |
Map<String, List<String>> multipartparams; |
|
| 608 |
|
|
| 609 |
try |
|
| 610 |
{
|
|
| 611 |
//String req = IOUtils.toString(request.getInputStream()); |
|
| 612 |
//logMetacat.debug("request: " + req);
|
|
| 613 |
//InputStream reqStr = IOUtils.toInputStream(req); |
|
| 614 |
InputStream reqStr = request.getInputStream(); |
|
| 615 |
|
|
| 616 |
//handle MMP inputs |
|
| 617 |
File tmpDir = getTempDirectory(); |
|
| 618 |
File tmpSMFile = new File(tmpDir + |
|
| 619 |
".sysmeta." + new Date().getTime() + ".tmp"); |
|
| 620 |
logMetacat.debug("temp dir: " + tmpDir.getAbsolutePath());
|
|
| 621 |
MultipartRequestResolver mrr = new MultipartRequestResolver( |
|
| 622 |
tmpDir.getAbsolutePath(), 1000000000, 0); |
|
| 623 |
MultipartRequest mr = mrr.resolveMultipart(request); |
|
| 624 |
logMetacat.debug("resolved multipart request");
|
|
| 625 |
Map<String, File> files = mr.getMultipartFiles(); |
|
| 626 |
if(files == null) |
|
| 627 |
{
|
|
| 628 |
throw new ServiceFailure("1202", "create/update must have multipart files with names 'object' and 'sysmeta'");
|
|
| 629 |
} |
|
| 630 |
logMetacat.debug("got multipart files");
|
|
| 631 |
|
|
| 632 |
if(files.keySet() == null) |
|
| 633 |
{
|
|
| 634 |
logMetacat.error("No file keys in MMP request.");
|
|
| 635 |
throw new ServiceFailure("1202", "No file keys found in MMP. " +
|
|
| 636 |
"create/update must have multipart files with names 'object' and 'sysmeta'"); |
|
| 637 |
} |
|
| 595 |
|
|
| 596 |
// Read the incoming data from its Mime Multipart encoding |
|
| 597 |
Map<String, File> files = collectMultipartFiles(); |
|
| 598 |
InputStream object = null; |
|
| 599 |
InputStream sysmeta = null; |
|
| 638 | 600 |
|
| 639 |
// for logging purposes, dump out the key-value pairs that constitute the request |
|
| 640 |
// 3 types exist: request params, multipart params, and multipart files |
|
| 641 |
Iterator it = files.keySet().iterator(); |
|
| 642 |
logMetacat.debug("iterating through request parts: " + it);
|
|
| 643 |
while(it.hasNext()) |
|
| 644 |
{
|
|
| 645 |
String key = (String)it.next(); |
|
| 646 |
logMetacat.debug("files key: " + key);
|
|
| 647 |
logMetacat.debug("files value: " + files.get(key));
|
|
| 648 |
} |
|
| 649 |
|
|
| 650 |
multipartparams = mr.getMultipartParameters(); |
|
| 651 |
it = multipartparams.keySet().iterator(); |
|
| 652 |
while(it.hasNext()) |
|
| 653 |
{
|
|
| 654 |
String key = (String)it.next(); |
|
| 655 |
logMetacat.debug("multipartparams key: " + key);
|
|
| 656 |
logMetacat.debug("multipartparams value: " + multipartparams.get(key));
|
|
| 657 |
} |
|
| 658 |
|
|
| 659 |
it = params.keySet().iterator(); |
|
| 660 |
while(it.hasNext()) |
|
| 661 |
{
|
|
| 662 |
String key = (String)it.next(); |
|
| 663 |
logMetacat.debug("param key: " + key);
|
|
| 664 |
logMetacat.debug("param value: " + params.get(key));
|
|
| 665 |
} |
|
| 666 |
logMetacat.debug("done iterating the request...");
|
|
| 601 |
File smFile = files.get("sysmeta");
|
|
| 602 |
sysmeta = new FileInputStream(smFile); |
|
| 603 |
File objFile = files.get("object");
|
|
| 604 |
object = new FileInputStream(objFile); |
|
| 605 |
|
|
| 606 |
if ( action.equals(FUNCTION_NAME_INSERT)) { //handle inserts
|
|
| 667 | 607 |
|
| 668 |
File smFile = files.get("sysmeta");
|
|
| 669 |
if (smFile == null) |
|
| 670 |
throw new InvalidRequest("1102", "Missing the required file-part 'sysmeta' from the multipart request.");
|
|
| 671 |
logMetacat.debug("smFile: " + smFile.getAbsolutePath());
|
|
| 672 |
sysmeta = new FileInputStream(smFile); |
|
| 673 |
File objFile = files.get("object");
|
|
| 674 |
if (objFile == null) |
|
| 675 |
throw new InvalidRequest("1102", "Missing the required file-part 'object' from the multipart request.");
|
|
| 608 |
logMetacat.debug("Commence creation...");
|
|
| 609 |
SystemMetadata smd = (SystemMetadata) deserializeServiceType(SystemMetadata.class, sysmeta); |
|
| 676 | 610 |
|
| 677 |
logMetacat.debug("objectfile: " + objFile.getAbsolutePath());
|
|
| 678 |
object = new FileInputStream(objFile); |
|
| 679 |
|
|
| 680 |
/*String obj = IOUtils.toString(object); |
|
| 681 |
String sm = IOUtils.toString(sysmeta); |
|
| 682 |
logMetacat.debug("object: " + obj);
|
|
| 683 |
logMetacat.debug("sm: " + sm);
|
|
| 684 |
object = IOUtils.toInputStream(obj); |
|
| 685 |
sysmeta = IOUtils.toInputStream(sm);*/ |
|
| 686 |
|
|
| 687 |
} |
|
| 688 |
catch(org.apache.commons.fileupload.FileUploadException fue) |
|
| 689 |
{
|
|
| 690 |
throw new ServiceFailure("1202", "Could not upload MMP files: " + fue.getMessage());
|
|
| 691 |
} |
|
| 692 |
catch(IOException ioe) |
|
| 693 |
{
|
|
| 694 |
throw new ServiceFailure("1202",
|
|
| 695 |
"IOException when processing Mime Multipart: " + ioe.getMessage()); |
|
| 696 |
} |
|
| 697 |
catch(Exception e) |
|
| 698 |
{
|
|
| 699 |
throw new ServiceFailure("1202", "Error handling MMP upload: " + e.getClass() + ": " + e.getMessage());
|
|
| 700 |
} |
|
| 611 |
Identifier id = new Identifier(); |
|
| 612 |
id.setValue(pid); |
|
| 613 |
logMetacat.debug("creating object with pid " + id.getValue());
|
|
| 614 |
Identifier rId = CNodeService.getInstance().create(session, id, object, smd); |
|
| 701 | 615 |
|
| 702 |
if ( action.equals(FUNCTION_NAME_INSERT)) { //handle inserts
|
|
| 703 |
|
|
| 704 |
// Check if the objectId exists |
|
| 705 |
IdentifierManager im = IdentifierManager.getInstance(); |
|
| 706 |
if (im.identifierExists(pid)) {
|
|
| 707 |
throw new IdentifierNotUnique("1000", "Identifier is already in use: " + pid);
|
|
| 708 |
} |
|
| 709 |
|
|
| 710 |
logMetacat.debug("Commence creation...");
|
|
| 711 |
IBindingFactory bfact = |
|
| 712 |
BindingDirectory.getFactory(SystemMetadata.class); |
|
| 713 |
IUnmarshallingContext uctx = bfact.createUnmarshallingContext(); |
|
| 714 |
SystemMetadata smd = (SystemMetadata) uctx.unmarshalDocument(sysmeta, null); |
|
| 715 |
|
|
| 716 |
Identifier id = new Identifier(); |
|
| 717 |
id.setValue(pid); |
|
| 718 |
logMetacat.debug("creating object with pid " + id.getValue());
|
|
| 719 |
Identifier rId = CNodeService.getInstance().create(session, id, object, smd); |
|
| 720 |
serializeServiceType(Identifier.class, rId, out); |
|
| 721 |
|
|
| 722 |
} else {
|
|
| 723 |
throw new InvalidRequest("1000", "Operation must be create or update.");
|
|
| 724 |
} |
|
| 616 |
OutputStream out = response.getOutputStream(); |
|
| 617 |
response.setStatus(200); |
|
| 618 |
response.setContentType("text/xml");
|
|
| 725 | 619 |
|
| 726 |
//clean up the MMP files |
|
| 727 |
//parts.get("systemmetadata").delete();
|
|
| 728 |
//parts.get("object").delete();
|
|
| 729 |
} catch (NotAuthorized e) {
|
|
| 730 |
response.setStatus(500); |
|
| 731 |
serializeException(e, out); |
|
| 732 |
} catch (InvalidToken e) {
|
|
| 733 |
response.setStatus(500); |
|
| 734 |
serializeException(e, out); |
|
| 735 |
} catch (ServiceFailure e) {
|
|
| 736 |
response.setStatus(500); |
|
| 737 |
serializeException(e, out); |
|
| 738 |
} catch (IdentifierNotUnique e) {
|
|
| 739 |
response.setStatus(500); |
|
| 740 |
serializeException(e, out); |
|
| 741 |
} catch (UnsupportedType e) {
|
|
| 742 |
response.setStatus(500); |
|
| 743 |
serializeException(e, out); |
|
| 744 |
} catch (InsufficientResources e) {
|
|
| 745 |
response.setStatus(500); |
|
| 746 |
serializeException(e, out); |
|
| 747 |
} catch (InvalidSystemMetadata e) {
|
|
| 748 |
response.setStatus(500); |
|
| 749 |
serializeException(e, out); |
|
| 750 |
} catch (NotImplemented e) {
|
|
| 751 |
response.setStatus(500); |
|
| 752 |
serializeException(e, out); |
|
| 753 |
} catch (InvalidRequest e) {
|
|
| 754 |
response.setStatus(500); |
|
| 755 |
serializeException(e, out); |
|
| 756 |
} /*catch (MessagingException e) {
|
|
| 757 |
ServiceFailure sf = new ServiceFailure("1000", e.getMessage());
|
|
| 758 |
serializeException(sf, out); |
|
| 759 |
} catch (IOException e) {
|
|
| 760 |
response.setStatus(500); |
|
| 761 |
ServiceFailure sf = new ServiceFailure("1000", e.getMessage());
|
|
| 762 |
serializeException(sf, out); |
|
| 763 |
}*/ catch (JiBXException e) {
|
|
| 764 |
response.setStatus(500); |
|
| 765 |
e.printStackTrace(System.out); |
|
| 766 |
InvalidSystemMetadata ism = new InvalidSystemMetadata("1080", e.getMessage());
|
|
| 767 |
serializeException(ism, out); |
|
| 620 |
serializeServiceType(Identifier.class, rId, out); |
|
| 621 |
|
|
| 622 |
} else {
|
|
| 623 |
throw new InvalidRequest("1000", "Operation must be create.");
|
|
| 768 | 624 |
} |
| 769 | 625 |
} |
| 770 | 626 |
|
| ... | ... | |
| 974 | 830 |
/** |
| 975 | 831 |
* Register System Metadata without data or metadata object |
| 976 | 832 |
* @param pid identifier for System Metadata entry |
| 833 |
* @throws JiBXException |
|
| 834 |
* @throws FileUploadException |
|
| 835 |
* @throws IOException |
|
| 836 |
* @throws InvalidRequest |
|
| 837 |
* @throws ServiceFailure |
|
| 838 |
* @throws InvalidSystemMetadata |
|
| 839 |
* @throws NotAuthorized |
|
| 840 |
* @throws NotImplemented |
|
| 977 | 841 |
*/ |
| 978 |
protected void registerSystemMetadata(String pid) {
|
|
| 842 |
protected boolean registerSystemMetadata(String pid) throws ServiceFailure, InvalidRequest, IOException, FileUploadException, JiBXException, NotImplemented, NotAuthorized, InvalidSystemMetadata {
|
|
| 979 | 843 |
logMetacat.debug("Entering registerSystemMetadata: " + pid);
|
| 980 |
OutputStream out = null; |
|
| 981 |
try {
|
|
| 982 |
out = response.getOutputStream(); |
|
| 983 |
response.setStatus(200); |
|
| 984 |
response.setContentType("text/xml");
|
|
| 985 |
} catch (IOException e1) {
|
|
| 986 |
logMetacat.error("Could not get the output stream for writing in putObject");
|
|
| 987 |
} |
|
| 988 |
try {
|
|
| 989 | 844 |
|
| 990 |
// Read the incoming data from its Mime Multipart encoding |
|
| 991 |
logMetacat.debug("Disassembling MIME multipart form");
|
|
| 992 |
InputStream sysmeta = null; |
|
| 993 |
Map<String, List<String>> multipartparams; |
|
| 845 |
// get the system metadata from the request |
|
| 846 |
SystemMetadata systemMetadata = collectSystemMetadata(); |
|
| 994 | 847 |
|
| 995 |
try {
|
|
| 996 |
|
|
| 997 |
// handle MMP inputs |
|
| 998 |
File tmpDir = getTempDirectory(); |
|
| 999 |
|
|
| 1000 |
logMetacat.debug("temp dir: " + tmpDir.getAbsolutePath());
|
|
| 1001 |
MultipartRequestResolver mrr = new MultipartRequestResolver( |
|
| 1002 |
tmpDir.getAbsolutePath(), 1000000000, 0); |
|
| 1003 |
MultipartRequest mr = mrr.resolveMultipart(request); |
|
| 1004 |
logMetacat.debug("resolved multipart request");
|
|
| 1005 |
Map<String, File> files = mr.getMultipartFiles(); |
|
| 1006 |
if (files == null) {
|
|
| 1007 |
throw new ServiceFailure("1202",
|
|
| 1008 |
"register meta must have multipart file with name 'sysmeta'"); |
|
| 1009 |
} |
|
| 1010 |
logMetacat.debug("got multipart files");
|
|
| 1011 |
|
|
| 1012 |
if (files.keySet() == null) {
|
|
| 1013 |
logMetacat.error("No file keys in MMP request.");
|
|
| 1014 |
throw new ServiceFailure( |
|
| 1015 |
"1202", |
|
| 1016 |
"No file keys found in MMP. " |
|
| 1017 |
+ "register meta must have multipart file with name 'sysmeta'"); |
|
| 1018 |
} |
|
| 1019 |
|
|
| 1020 |
// for logging purposes, dump out the key-value pairs that |
|
| 1021 |
// constitute the request |
|
| 1022 |
// 3 types exist: request params, multipart params, and |
|
| 1023 |
// multipart files |
|
| 1024 |
Iterator it = files.keySet().iterator(); |
|
| 1025 |
logMetacat.debug("iterating through request parts: " + it);
|
|
| 1026 |
while (it.hasNext()) {
|
|
| 1027 |
String key = (String) it.next(); |
|
| 1028 |
logMetacat.debug("files key: " + key);
|
|
| 1029 |
logMetacat.debug("files value: " + files.get(key));
|
|
| 1030 |
} |
|
| 1031 |
|
|
| 1032 |
multipartparams = mr.getMultipartParameters(); |
|
| 1033 |
it = multipartparams.keySet().iterator(); |
|
| 1034 |
while (it.hasNext()) {
|
|
| 1035 |
String key = (String) it.next(); |
|
| 1036 |
logMetacat.debug("multipartparams key: " + key);
|
|
| 1037 |
logMetacat.debug("multipartparams value: "
|
|
| 1038 |
+ multipartparams.get(key)); |
|
| 1039 |
} |
|
| 1040 |
|
|
| 1041 |
it = params.keySet().iterator(); |
|
| 1042 |
while (it.hasNext()) {
|
|
| 1043 |
String key = (String) it.next(); |
|
| 1044 |
logMetacat.debug("param key: " + key);
|
|
| 1045 |
logMetacat.debug("param value: " + params.get(key));
|
|
| 1046 |
} |
|
| 1047 |
logMetacat.debug("done iterating the request...");
|
|
| 1048 |
|
|
| 1049 |
File smFile = files.get("sysmeta");
|
|
| 1050 |
if (smFile == null) {
|
|
| 1051 |
throw new InvalidRequest("1102",
|
|
| 1052 |
"Missing the required file-part 'sysmeta' from the multipart request."); |
|
| 1053 |
} |
|
| 1054 |
logMetacat.debug("smFile: " + smFile.getAbsolutePath());
|
|
| 1055 |
sysmeta = new FileInputStream(smFile); |
|
| 1056 |
|
|
| 1057 |
} catch (org.apache.commons.fileupload.FileUploadException fue) {
|
|
| 1058 |
throw new ServiceFailure("1202", "Could not upload MMP files: "
|
|
| 1059 |
+ fue.getMessage()); |
|
| 1060 |
} catch (IOException ioe) {
|
|
| 1061 |
throw new ServiceFailure("1202",
|
|
| 1062 |
"IOException when processing Mime Multipart: " |
|
| 1063 |
+ ioe.getMessage()); |
|
| 1064 |
} catch (Exception e) {
|
|
| 1065 |
throw new ServiceFailure("1202", "Error handling MMP upload: "
|
|
| 1066 |
+ e.getClass() + ": " + e.getMessage()); |
|
| 1067 |
} |
|
| 1068 |
|
|
| 1069 |
// Check if the objectId exists |
|
| 1070 |
IdentifierManager im = IdentifierManager.getInstance(); |
|
| 1071 |
if (im.identifierExists(pid)) {
|
|
| 1072 |
throw new IdentifierNotUnique("1000",
|
|
| 1073 |
"Identifier is already in use: " + pid); |
|
| 1074 |
} |
|
| 1075 |
|
|
| 1076 |
logMetacat.debug("Commence creation...");
|
|
| 1077 |
IBindingFactory bfact = BindingDirectory |
|
| 1078 |
.getFactory(SystemMetadata.class); |
|
| 1079 |
IUnmarshallingContext uctx = bfact.createUnmarshallingContext(); |
|
| 1080 |
SystemMetadata systemMetadata = (SystemMetadata) uctx |
|
| 1081 |
.unmarshalDocument(sysmeta, null); |
|
| 1082 |
|
|
| 1083 |
Identifier guid = new Identifier(); |
|
| 1084 |
guid.setValue(pid); |
|
| 1085 |
logMetacat.debug("registering system metadata with pid "
|
|
| 1086 |
+ guid.getValue()); |
|
| 1087 |
boolean result = CNodeService.getInstance().registerSystemMetadata( |
|
| 1088 |
session, guid, systemMetadata); |
|
| 1089 |
serializeServiceType(Boolean.class, result, out); |
|
| 1090 |
|
|
| 1091 |
} catch (NotAuthorized e) {
|
|
| 1092 |
response.setStatus(500); |
|
| 1093 |
serializeException(e, out); |
|
| 1094 |
} catch (ServiceFailure e) {
|
|
| 1095 |
response.setStatus(500); |
|
| 1096 |
serializeException(e, out); |
|
| 1097 |
} catch (IdentifierNotUnique e) {
|
|
| 1098 |
response.setStatus(500); |
|
| 1099 |
serializeException(e, out); |
|
| 1100 |
} catch (NotImplemented e) {
|
|
| 1101 |
response.setStatus(500); |
|
| 1102 |
serializeException(e, out); |
|
| 1103 |
} catch (InvalidRequest e) {
|
|
| 1104 |
response.setStatus(500); |
|
| 1105 |
serializeException(e, out); |
|
| 1106 |
} catch (JiBXException e) {
|
|
| 1107 |
response.setStatus(500); |
|
| 1108 |
e.printStackTrace(System.out); |
|
| 1109 |
InvalidSystemMetadata ism = new InvalidSystemMetadata("1080", e
|
|
| 1110 |
.getMessage()); |
|
| 1111 |
serializeException(ism, out); |
|
| 1112 |
} catch (InvalidSystemMetadata e) {
|
|
| 1113 |
serializeException(e, out); |
|
| 1114 |
} |
|
| 848 |
Identifier guid = new Identifier(); |
|
| 849 |
guid.setValue(pid); |
|
| 850 |
logMetacat.debug("registering system metadata with pid " + guid.getValue());
|
|
| 851 |
boolean result = CNodeService.getInstance().registerSystemMetadata(session, guid, systemMetadata); |
|
| 852 |
|
|
| 853 |
response.setStatus(200); |
|
| 854 |
response.setContentType("text/xml");
|
|
| 855 |
return result; |
|
| 856 |
|
|
| 1115 | 857 |
} |
| 1116 | 858 |
|
| 1117 | 859 |
/** |
Also available in: Unified diff
consolidate multi part handling in the super class - subclasses need only call the appropriate helper to get access to the needed resources. superclass does some validation to make sure the files are in place in the request