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01 Access Credential Acquisition

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1.1 Public Cloud Usage

DocFlow uses TextIn accounts. Please contact Intsig’s sales team to obtain your TextIn Account. Use TextIn Account to login and get x-ti-app-id and x-ti-secret-code from Textin console API Keys & Account.

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1.2 Private Cloud Usage

Please contact the technical support personnel you are working with to obtain API call credentials for on-prem deployment.

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02 Request Authentication

DocFlow interface supports two request authentication methods:
  1. Simple Authentication. This method is simple but has limited security, usually used for quick integration to experience DocFlow processes and effects.
  2. Signature Authentication. This method is complex but has higher security. It can prevent access credentials from being obtained by man-in-the-middle attacks and tampering with requests.

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2.1 Simple Authentication

Use x-ti-app-id and x-ti-secret-code as HTTP headers for authentication. Example: 
curl \
  -H "x-ti-app-id: <your-app-id>" \
  -H "x-ti-secret-code: <your-secret-code>" \
  "https://docflow.textin.ai/api/app-api/sip/platform/v2/file/upload"

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2.2 Signature Authentication

Authenticate requests using signatures, requiring 3 HTTP Headers:
HeaderDescription
x-ti-app-idx-ti-app-id obtained from TextIn developer information
x-ti-timestampUnix Epoch timestamp, in seconds
x-ti-signatureRequest signature, calculation method described below

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Signature Calculation

The signature calculation method is: 
signature = lower(hex(HMAC_SHA256(signing_key, string_to_sign)))
Notes:
  1. lower() is the lowercase letter conversion function
  2. hex() converts byte array to hexadecimal string
  3. HMAC_SHA256 is a cryptographic hash function, refer to libraries in various development languages
  4. signing_key = HMAC_SHA256(x-ti-secret-code, epoch). Where x-ti-secret-code is the TextIn developer credential. epoch is the Unix Epoch timestamp (seconds).
  5. string_to_sign, detailed explanation below
string_to_sign
string_to_sign is a string concatenated from the following content: 
"HTTP Method" + "\n"
"Request URL" + "\n"
"Sorted URL Parameters" + "\n"
"sha256(HTTP Request Body)"
Notes:
  1. HTTP method is uppercase, e.g., GET, POST
  2. Request URL, the path part of the URL (excluding protocol and domain), e.g., /api/app-api/sip/platform/v2/file/upload
  3. URL parameter sorting sorts all request parameters in ascending order by parameter name dictionary order (ASCII code). Parameter values do not participate in sorting. For example: Suppose the parameters are workspace_id=12345&batch_num=54321&file_name=invoice.pdf,
    The sorted result is batch_num=54321&file_name=invoice.pdf&workspace_id=12345.     Important:
    1. Parameter values do not need url encoding when performing signature calculation
    2. Parameters are joined with &, with no & at the end
Example: 
import requests
from requests_toolbelt.multipart.encoder import MultipartEncoder
import hashlib
import hmac
import time

ti_app_id = "your-app-id"
ti_secret_code = "your-app-secret"
filename = "file.pdf"
filepath = "/path/to/your/file.pdf"
params = {"workspace_id":"1871454238893576192","category":"采购订单"}

epoch_time = int(time.time())
http_method = "POST"
url = "/api/app-api/sip/platform/v2/file/upload"

payload = MultipartEncoder(
    fields={
        "file": (filename, open(filepath, "rb"), "application/pdf"),
    }
)

signing_key = hmac.new(ti_secret_code.encode('utf-8'), str(epoch_time).encode('utf-8'), hashlib.sha256).digest()
payload_raw = payload.to_string()
payload_hash = hashlib.sha256(payload_raw).hexdigest()
string_to_sign = f"{http_method}\n{url}\n{'&'.join(f'{k}={v}' for k, v in sorted(params.items()))}\n{payload_hash}"
signature = hmac.new(signing_key, string_to_sign.encode('utf-8'), hashlib.sha256).hexdigest()

print(f"epoch_time: {epoch_time}")
print(f"http_method: {http_method}")
print(f"signing_key: {signing_key}")
print(f"payload_hash: {payload_hash}")
print(f"string_to_sign: {string_to_sign}")
print(f"signature: {signature}")

resp = requests.post(url=f"https://docflow.textin.ai{url}", 
                     params=params, 
                     data=payload_raw, 
                     headers={"Content-Type": payload.content_type,
                              "x-ti-app-id": ti_app_id,
                              "x-ti-timestamp": str(epoch_time),
                              "x-ti-signature": signature,
                              })

print(resp.text)