Merge pull request #7 from jina-ai/docs-readme-usage

README.md

@@ -2,3 +2,28 @@
 
 PDFSegmenter is an Executor used for extracting images and text as chunks from PDF data. It stores each images and text of each page as chunks separately, with their respective mime types. It uses the [pdfplumber](https://github.com/jsvine/pdfplumber) library.
 
+## Loading data
+
+The `PDFSegmenter` expects data to be found in the `Document`'s `.blob` attribute. This can be loaded from a PDF file like so
+
+```python
+from docarray import DocumentArray, Document
+from jina import Flow
+
+doc = DocumentArray([Document(uri='cats_are_awesome.pdf')]) # adjust to your own pdf
+doc[0].load_uri_to_blob()
+print(doc[0])
+
+f = Flow().add(
+    uses='jinahub+docker://PDFSegmenter',
+)
+with f:
+    resp = f.post(on='/craft', inputs=doc)
+    print(f'{[c.mime_type for c in resp[0].chunks]}')
+```
+
+
+```
+>> <Document ('id', 'blob', 'mime_type', 'uri') at 9d77e00f759bf8523e86abf452ac28a0> # notice `.blob` field is set
+>> ['image/*', 'image/*', 'text/plain'] # we get both images and text from a PDF
+```