Resizing and Serving images on Google Cloud Storage

Resize your image files on Google Cloud storage with Images Python API powered by Google.

Setup

1. Clone this repo.

git clone https://github.com/albertcht/python-gcs-image.git

2. Install the requirements. (Flask)

pip install -r requirements.txt -t lib

3. Deploy to App Engine.

gcloud app deploy

Usage

1. Get a serving url from existed file on Google Cloud Storage:

curl https://PROJECT_NAME.appspot.com/image-url?bucket=mybuckey&image=image_name.jpg

2. It will return a url that looks something like:

https://lh3.googleusercontent.com/93uhV8K2yHkRuD63KJxlTi7SxjHS8my2emuHmGLZxEmX99_XAjTN3c_2zmKVb3XQ5d8FEkwtgbGjyYpaDQg

Reminders

1. Only one app can "own" the image. As stated in the documentation for get_serving_url:

If you serve images from Google Cloud Storage, you cannot serve an image from two separate apps. Only the first app that calls get_serving_url on the image can get the URL to serve it because that app has obtained ownership of the image.

2. The serving url is inherently public (no support for private serving urls).

Google Cloud Storage Setup

Note you need to grant Storage Object Admin access on your GCS objects to a GAE service account responsible for generating URLs, which looks like:

your-project-id@appspot.gserviceaccount.com

gsutil Commands for Reference

# Create a new bucket.
gsutil mb -p <project> gs://<bucket>

# Set the default ACL for objects uploaded to the bucket. Note the below
# command grants OWNER access to the service account.
gsutil defacl ch -u account@example.com:O gs://<bucket>

# If using the web uploader you will also need to grant access to the service
# account to create objects.
gsutil acl ch -u account@example.com:O gs://<bucket>

# Ensure that the files are set with `public-read` permissions. URLs generated
# by the images service respect GCS object permissions so if you intend to serve
# them publicly, they will need to be `public-read`. Adjust the default ACL with
# the command below.
gsutil defacl set public-read gs://<bucket>

# Upload assets to the Google Cloud Storage bucket.
gsutil cp file.jpg gs://<bucket>/<path>/

Examples

• By default it returns an image of a maximum length of 512px. (link)

• By appending the =sXX to the end of it where XX can be any integer in the range of 0–1600 and it will result to scale down the image to longest dimension without affecting the original aspect ratio. (link =s256)

• By appending =sXX-c a cropped version of that image is being returned as a response. (link =s400-c)

• By appending =pp-br100-rp-s200 the image is smartly cropped, border 100%, format PNG and size is 200. (link =pp-br100-rp-s200)

• By appending =pp-br100-rp-s200 the image is smartly cropped, width 100, height 300, quality 100, format JPG. (link =w100-h300-c-pp-l100-rj)

• By appending =s0 (s zero) the original image is being returned without any resize or modification. (link =s0)

Advanced Parameters

SIZE / CROP

• s640 — generates image 640 pixels on largest dimension
• s0 — original size image
• w100 — generates image 100 pixels wide
• h100 — generates image 100 pixels tall
• s (without a value) — stretches image to fit dimensions
• c — crops image to provided dimensions
• n — same as c, but crops from the center
• p — smart square crop, attempts cropping to faces
• pp — alternate smart square crop, does not cut off faces (?)
• cc — generates a circularly cropped image
• ci — square crop to smallest of: width, height, or specified =s parameter
• nu — no-upscaling. Disables resizing an image to larger than its original resolution.

ROTATION

• fv — flip vertically
• fh — flip horizontally
• r{90, 180, 270} — rotates image 90, 180, or 270 degrees clockwise

IMAGE FORMAT

• rj — forces the resulting image to be JPG

• rp — forces the resulting image to be PNG

• rw — forces the resulting image to be WebP

• rg — forces the resulting image to be GIF

• v{0,1,2,3} — sets image to a different format option (works with JPG and WebP)

Forcing PNG, WebP and GIF outputs can work in combination with circular crops for a transparent background. Forcing JPG can be combined with border color to fill in backgrounds in transparent images.

ANIMATED GIFs

• rh — generates an MP4 from the input image
• k — kill animation (generates static image)

Filters

• fSoften=1,100,0: - where 100 can go from 0 to 100 to blur the image
• fVignette=1,100,1.4,0,000000 where 100 controls the size of the gradient and 000000 is RRGGBB of the color of the border shadow
• fInvert=0,1 inverts the image regardless of the value provided
• fbw=0,1 makes the image black and white regardless of the value provided

MISC.

• b10 — add a 10px border to image
• c0xAARRGGBB — set border color, eg. =c0xffff0000 for red
• d — adds header to cause browser download
• e7 — set cache-control max-age header on response to 7 days
• l100 — sets JPEG quality to 100% (1-100)
• h — responds with an HTML page containing the image
• g — responds with XML used by Google's pan/zoom

Full Reference

int:  s   ==> Size
int:  w   ==> Width
bool: c   ==> Crop
hex:  c   ==> BorderColor
bool: d   ==> Download
int:  h   ==> Height
bool: s   ==> Stretch
bool: h   ==> Html
bool: p   ==> SmartCrop
bool: pa  ==> PreserveAspectRatio
bool: pd  ==> Pad
bool: pp  ==> SmartCropNoClip
bool: pf  ==> SmartCropUseFace
int:  p   ==> FocalPlane
bool: n   ==> CenterCrop
int:  r   ==> Rotate
bool: r   ==> SkipRefererCheck
bool: fh  ==> HorizontalFlip
bool: fv  ==> VerticalFlip
bool: cc  ==> CircleCrop
bool: ci  ==> ImageCrop
bool: o   ==> Overlay
str:  o   ==> EncodedObjectId
str:  j   ==> EncodedFrameId
int:  x   ==> TileX
int:  y   ==> TileY
int:  z   ==> TileZoom
bool: g   ==> TileGeneration
bool: fg  ==> ForceTileGeneration
bool: ft  ==> ForceTransformation
int:  e   ==> ExpirationTime
str:  f   ==> ImageFilter
bool: k   ==> KillAnimation
int:  k   ==> FocusBlur
bool: u   ==> Unfiltered
bool: ut  ==> UnfilteredWithTransforms
bool: i   ==> IncludeMetadata
bool: ip  ==> IncludePublicMetadata
bool: a   ==> EsPortraitApprovedOnly
int:  a   ==> SelectFrameint
int:  m   ==> VideoFormat
int:  vb  ==> VideoBegin
int:  vl  ==> VideoLength
bool: lf  ==> LooseFaceCrop
bool: mv  ==> MatchVersion
bool: id  ==> ImageDigest
int:  ic  ==> InternalClient
bool: b   ==> BypassTakedown
int:  b   ==> BorderSize
str:  t   ==> Token
str:  nt0 ==> VersionedToken
bool: rw  ==> RequestWebp
bool: rwu ==> RequestWebpUnlessMaybeTransparent
bool: rwa ==> RequestAnimatedWebp
bool: nw  ==> NoWebp
bool: rh  ==> RequestH264
bool: nc  ==> NoCorrectExifOrientation
bool: nd  ==> NoDefaultImage
bool: no  ==> NoOverlay
str:  q   ==> QueryString
bool: ns  ==> NoSilhouette
int:  l   ==> QualityLevel
int:  v   ==> QualityBucket
bool: nu  ==> NoUpscale
bool: rj  ==> RequestJpeg
bool: rp  ==> RequestPng
bool: rg  ==> RequestGif
bool: pg  ==> TilePyramidAsProto
bool: mo  ==> Monogram
bool: al  ==> Autoloop
int:  iv  ==> ImageVersion
int:  pi  ==> PitchDegrees
int:  ya  ==> YawDegrees
int:  ro  ==> RollDegrees
int:  fo  ==> FovDegrees
bool: df  ==> DetectFaces
str:  mm  ==> VideoMultiFormat
bool: sg  ==> StripGoogleData
bool: gd  ==> PreserveGoogleData
bool: fm  ==> ForceMonogram
int:  ba  ==> Badge
int:  br  ==> BorderRadius
hex:  bc  ==> BackgroundColor
hex:  pc  ==> PadColor
hex:  sc  ==> SubstitutionColor
bool: dv  ==> DownloadVideo
bool: md  ==> MonogramDogfood
int:  cp  ==> ColorProfile
bool: sm  ==> StripMetadata
int:  cv  ==> FaceCropVersion

Reference:

• https://stackoverflow.com/questions/25148567/list-of-all-the-app-engine-images-service-get-serving-url-uri-options
• https://medium.com/google-cloud/uploading-resizing-and-serving-images-with-google-cloud-platform-ca9631a2c556