add stream-helper.sh script

README.md

@@ -95,6 +95,8 @@ curl -u user:password sftp://hostname/path/to/image.bmap > image.bmap
 curl -u user:password sftp://hostname/path/to/image.gz | bmap-writer - image.bmap /dev/sdX
 ```
 
+Note: the [stream-helper.sh](stream-helper.sh) script can be used for stream processing tasks.
+
 ## Yocto Integration
 
 `bmap-writer` is already available in [meta-openembedded](https://github.com/openembedded/meta-openembedded/blob/master/meta-oe/recipes-support/bmap-writer/bmap-writer_git.bb).

bmap-writer-test.sh

@@ -116,6 +116,6 @@ echo "## Write the file with bmap-writer and zstd from HTTP server"
 python3 -m http.server -d $(pwd) -b 127.0.0.1 8987 &
 SERVER_PID=$!
 sleep 2
-wget -q -O - http://127.0.0.1:8987/test.img.zst | ./bmap-writer - test.img.bmap test5.zst.img.out
+./stream-helper.sh http://127.0.0.1:8987/test.img.zst test5.zst.img.out
 cmp test.img.out test5.zst.img.out
 kill $SERVER_PID

stream-helper.sh

@@ -0,0 +1,29 @@
+#!/bin/bash -ex
+
+export PATH=$PWD:$PATH
+
+IMAGE_URL=$(echo "$1" | grep -P '^(https?|s?ftp)://([\da-zA-Z\.-]+)(:\d+)?(/[^\s]*)?$' > /dev/null && echo "$1" || echo "")
+DEVICE=$2
+
+WGET=$(which wget)
+BMAP_WRITER=$(which bmap-writer)
+
+if [ -z "$IMAGE_URL" ]; then
+    echo "Usage: $0 <url> <device>"
+    exit 1
+fi
+
+if [ -z "$WGET" ] && [ -z "$BMAP_WRITER" ]; then
+    echo "Please install wget/bmap-writer"
+    exit 1
+fi
+
+BMAP_URL=$(echo "$IMAGE_URL" | sed 's/\.[^.]*$/.bmap/')
+BMAP_FILE=$(echo "$BMAP_URL" | sed 's/.*\///')
+
+BMAP_FILE="${BMAP_FILE}_"
+echo "Downloading $BMAP_URL to $BMAP_FILE"
+$WGET -q $BMAP_URL -O $BMAP_FILE
+echo "Streaming $IMAGE_URL to $DEVICE"
+$WGET -q $IMAGE_URL -O - | $BMAP_WRITER - $BMAP_FILE $DEVICE
+exit 0