question

Upvotes
Accepted
kai fang avatar image
1 ●3 ●2 ●4

AWS File Extraction not working properly

I try to get the stream file of my schedule task, and read it into python, using the rest api call, using the following headers:

headers = {'Authorization': 'Token %s' % auth, 'Prefer': 'respond-async', 'Accept-Charset': 'UTF-8', 'Content-Type': 'application/json',"X-Direct-Download":"true"}

When i do not include X-Direct-Download, i only get part of the data, compared to the csv file i directly download in the web GUI, however, by adding this, i get some text result like the following:

'\x1f�\x08\x00\x00\x00\x00\x00\x00\x00�][s\x1c�n~?��u�\x1aw��\x17��\x12m1�(\x15I%�_T�M�RŖO,�R��\x01fv�;3��Pܥ\x1d\x17�ds���h4\x1a@��/���V�\x7f��������\x7f�yr�\u19db�\u05ef�'

which is clearly not correct. Is there any way to get correct full file as a stream in aws enviorment.

full code:

result = simple_get("/Extractions/ExtractedFiles('%s')/$value" % file_id, auth)

where:

def simple_get(endpoint, auth):

headers = {'Authorization': 'Token %s' % auth, 'Prefer': 'respond-async', 'Accept-Charset': 'UTF-8', 'Content-Type': 'application/json',"X-Direct-Download":"true"}

r = requests.get(url_base + endpoint, headers=headers)

return r

dss-rest-apitick-history-rest-apiextraction
icon clock
10 |1500

Up to 2 attachments (including images) can be used with a maximum of 512.0 KiB each and 1.0 MiB total.

3 Answers

Upvotes
Accepted
Christiaan Meihsl avatar image
13.7k ●26 ●8 ●12

@@kf2449, in addition to the response by Jirapongse:

What you observe is actually gzipped data:

'\x1f�\x08\x00\x00\x00\x00\x00\x00\x00�][s\x1c�n~?��u�\x1aw��\x17��\x12m1�(\x15I%�_T�M�RŖO,�R��\x01fv�;3��Pܥ\x1d\x17�ds���h4\x1a@��/���V�\x7f��������\x7f�yr�\u19db�\u05ef�'

When handling the data, you are getting different behaviors due to the response headers, which differ between TRTH and AWS downloads.

TRTH returns the following content related headers:

Content-Encoding:gzip
Content-Type:text/plain

AWS returns different headers:

Content-Disposition:attachment; filename=_OnD_0x05de99857e5b3036.csv.gz
Content-Type:application/gzip

Your application reacts differently to these (many code libraries automatically decide to decompress data (or not) based on response headers), that is why you observe different data formats. It is best to set the appropriate headers and parameters to avoid such behavior. If you follow what is explained in the links sent by Jirapongse you should be able to download the entire file, in the correct format.

You can also look at the Python code samples set available under the downloads tab, and explained in this document. One of the samples (TRTH_Get_Latest_Schedule_Files) should be of help.

icon clock
10 |1500

Up to 2 attachments (including images) can be used with a maximum of 512.0 KiB each and 1.0 MiB total.

Upvotes
Jirapongse avatar image
53.2k ●138 ●44 ●63

@kf2449

To avoid incomplete output, you need to download the Gzip file and then decompress it. It was mentioned in this documentation ADVISORY: AVOID INCOMPLETE OUTPUT - DOWNLOAD THEN DECOMPRESS. You can also refer to this article: How to Optimize TRTH (Tick History) file downloads for Python (and other languages) for Python.

To download from AWS, please refer to Boost TRTH downloads with AWS.

icon clock
10 |1500

Up to 2 attachments (including images) can be used with a maximum of 512.0 KiB each and 1.0 MiB total.

Upvotes
veerapath.rungruengrayubkul avatar image
11.3k ●25 ●8 ●14

@kf2449

The response text likely is in gzip compression format. Normally, TRTH extraction provides data in gzip compress format. The Python Requests library automatically decompress data if the response header contains Content-Encoding="gzip". However, AWS does not set this header, so the Requests call does not decompress. Application needs to decompress data in separated call. Please see code example in the "TRTH Python Code" downloaded from this link.

icon clock
10 |1500

Up to 2 attachments (including images) can be used with a maximum of 512.0 KiB each and 1.0 MiB total.