XCEDE Web Services

2008 mBIRN AHM

San Juan, Puerto Rico

Use Case

• Run smoothing filter on all oasis-brains T1 scans for

subjects rated as ‘twisted’ by WashU and aged 30-

70 years old. Reupload the results with a tag of

'smoothed‘.

Pseudocode

subjs = FIND_SUBJECTS ( proj=OAS, age=30-70, washu:twistedness=400-700 )

foreach subj in subjs do

T1s = GET_FILE_RECORDS ( subj, tag=T1, format=NIfTI )

foreach T1 in T1s do

image = GET_FILE( T1.ID )

filteredT1 = filter( image )

UPLOAD ( filteredT1, subj, tag = "smoothed" )

done

done

Variables

• where:

• subjs : list of subject records (database UID)

• subj : subject record

• T1s : list of data records (includes image ID plus metadata)

• image, filteredT1 : image data

Services

• Services:

• - all services provide success/fail codes based on HTTP conventions

• - all output is in XCEDE XML or data files

• FIND_SUBJECTS

• - input: list of subject attributes (from fixed list of agreed basic terms that are

guaranteed, plus possible extra namespace qualified terms)

• - output: list of subject IDs that match all the attribute criteria

• - notes: this is not a generic search service with boolean combinations (client side

needs to implement any additional logic)

Services (continued)

• GET_FILE_RECORDS

• - input: subject ID, list of tags

• - output: data records

• GET_FILE

• - input: Unique ID from image record

• - output: image file

• UPLOAD

• - input: image file, subject ID, list of tags

• - output: none

Prototypes

• http://www.xcede.org/webServices/FIND_SUBJECTS?proj=OAS&age=30-

70&washu:twistedness=400-700

• --> returns XCEDE document

• http://www.xcede.org/webServices/GET_FILE_RECORDS?

subject=(subj)&tag=T1&format=NIfTI

• --> returns XCEDE document

• http://www.xcede.org/webServices/GET_FILE?ID=(id)

• --> returns binary file download

• http://www.xcede.org/webServices/UPLOAD?

image=filteredT1&subj=(subj)&tag=smoothed

• --> uploads file

Authentication Options

• https://www.xcede.org/webServices/SERVICE?arg1=ARG&arg2=ARG

• <-- requires username and password in header

• or

• https://www.xcede.org/webServices/SERVICE?

arg1=ARG&arg2=ARG&signature=289xcz9B3X21

• <-- signature is created by signing the rest of the URL using

• the user's private key (public key is registered when

• creating an account on the server or generally available)

• Assumptions: the single username and password is for the specified database and not

for other servers.

• Goal: provide workable authentication for testing, migrate to industry standards