---
sidebar_position: 1
sidebar_label: Overview
---

# Deployment

The OHIF Viewer can be served as a stand-alone PWA ([progressive web
application][pwa-url]) by building and hosting a collection of static assets or be embedded in other web applications via an iframe if needed. In
either case, you will need to configure your instance of the Viewer so that it
can connect to your data source (the database or PACS that provides the data
your Viewer will display).

:::tip
Our goal is to make deployment as simple and painless as possible; however,
there is an inherent amount of complexity in configuring and deploying web
applications. If you find yourself a little lost, please don't hesitate to
reach out to for help.
:::

## Deployment Scenarios

### Stand-alone Viewer

Deploying the OHIF Viewer as a stand-alone web application provides many
benefits, but comes at the cost of time and complexity. Some benefits include:

_Today:_

- Leverage [extensions](../platform/extensions/index.md) and
  [modes](../platform/modes/index.md) to drop-in powerful new features
- Add routes and customize the viewer's workflow
- Finer control over styling and whitelabeling

_In the future:_

- The ability to package the viewer for [App Store distribution][app-store]

#### Hosted Static Assets

At the end of the day, a production OHIF Viewer instance is a collection of
HTML, CSS, JS, Font Files, and Images. We "build" those files from our
`source code` with configuration specific to our project. We then make those
files publicly accessible by hosting them on a Web Server.

##### Part 1 - Build Production Assets

"Building", or creating, the files you will need is the same regardless of the
web host you choose. You can find detailed instructions on how to configure and
build the OHIF Viewer in our
["Build for Production" guide](./build-for-production.md).

##### Part 2 - Host Your App

There are a lot of [benefits to hosting static assets][host-static-assets] over
dynamic content. You can find instructions on how to host your build's output
via one of these guides:

_Drag-n-drop_

- [Netlify: Drop](./static-assets.md#netlify-drop)

_Easy_

- [Surge.sh](./static-assets.md#surgesh)
- [GitHub Pages](./static-assets.md#github-pages)

_Advanced_

- [AWS S3 + Cloudfront](./static-assets.md#aws-s3--cloudfront)
- [GCP + Cloudflare](./static-assets.md#gcp--cloudflare)
- [Azure](./static-assets.md#azure)

### Embedded Viewer (iframe)

`OHIF-v3` has deprecated deploying the viewer as an embedded viewer via a script
tag as the number of underlying libraries that run web workers are increasing for OHIF. An example of these libraries is OHIF's 3D rendering functionality that is provided by
`vtk-js`.

However, you can still embed the viewer using an iframe. You can utilize the iframe element to load the OHIF viewer and establish communication with it using the postMessage API if needed.
Read more about how to use the iframe [here](./iframe.md).


## Data

The OHIF Viewer is able to connect to any data source that implements the [DICOM
Web Standard][dicom-web-standard]. [DICOM Web][dicom-web] refers to RESTful
DICOM Services -- a recently standardized set of guidelines for exchanging
medical images and imaging metadata over the internet. Not all archives fully
support it yet, but it is gaining wider adoption.

### Configure Connection

If you have an existing archive and intend to host the OHIF Viewer at the same
domain name as your archive, then connecting the two is as simple as following
the steps layed out in our
[Configuration Essentials Guide](./../configuration/configurationFiles.md).

#### What if I don't have an imaging archive?

We provide some guidance on configuring a local image archive in our
[Data Source Essentials](./../configuration/dataSources/introduction.md)
guide. Hosting an archive remotely is a little trickier. You can check out some
of our [advanced recipes](#recipes) for modeled setups that may work for you.

#### What if I intend to host the OHIF Viewer at a different domain?

There are two important steps to making sure this setup works:

1. Your Image Archive needs to be exposed, in some way, to the open web. This
   can be directly, or through a `reverse proxy`, but the Viewer needs _some
   way_ to request its data.
2. \* Your Image Archive needs to have appropriate CORS (Cross-Origin Resource
   Sharing) Headers

> \* Cross-Origin Resource Sharing (CORS) is a mechanism that uses additional
> HTTP headers to tell a browser to let a web application running at one origin
> (domain) have permission to access selected resources from a server at a
> different origin. - [MDN Web Docs: Web - Http - CORS][cors]

Most image archives do not provide either of these features "out of the box".
It's common to use IIS, Nginx, or Apache to route incoming requests and append
appropriate headers. You can find an example of this setup in our
[Nginx + Image Archive Deployment Recipe](./nginx--image-archive.md).

#### What if my archive doesn't support DicomWeb?

It's possible to supply all Study data via JSON format, in the event you do not
have a DicomWeb endpoint. You can host all of the relevant files on any web
accessible server (Amazon S3, Azure Blob Storage, Local file server etc.)

This JSON is supplied via the '?url=' query parameter. It should reference an
endpoint that returns **application/json** formatted text.

If you do not have an API, you can simply return a text file containing the JSON
from any web server.

You tell the OHIF viewer to use JSON by using the `dicomjson` datasource and
appending `'?url='` query to your mode's route:

e.g.
`https://my-test-ohif-server/myMode/dicomjson?url=https://my-json-server/study-uid.json`

The returned JSON object must contain a single root object with a 'studies'
array.

You can read more about using different data sources for mode's routes
[here](../platform/modes/routes.md#route-path)

_Sample JSON format:_

```json
{
  "studies": [
    {
      "StudyInstanceUID": "1.2.840.113619.2.5.1762583153.215519.978957063.78",
      "StudyDescription": "BRAIN SELLA",
      "StudyDate": "20010108",
      "StudyTime": "120022",
      "PatientName": "MISTER^MR",
      "PatientId": "832040",
      "series": [
        {
          "SeriesDescription": "SAG T-1",
          "SeriesInstanceUID": "1.2.840.113619.2.5.1762583153.215519.978957063.121",
          "SeriesNumber": 2,
          "SeriesDate": "20010108",
          "SeriesTime": "120318",
          "Modality": "MR",
          "instances": [
            {
              "metadata": {
                "Columns": 512,
                "Rows": 512,
                "InstanceNumber": 3,
                "AcquisitionNumber": 0,
                "PhotometricInterpretation": "MONOCHROME2",
                "BitsAllocated": 16,
                "BitsStored": 16,
                "PixelRepresentation": 1,
                "SamplesPerPixel": 1,
                "PixelSpacing": [0.390625, 0.390625],
                "HighBit": 15,
                "ImageOrientationPatient": [0, 1, 0, 0, 0, -1],
                "ImagePositionPatient": [11.6, -92.5, 98.099998],
                "FrameOfReferenceUID": "1.2.840.113619.2.5.1762583153.223134.978956938.470",
                "ImageType": ["ORIGINAL", "PRIMARY", "OTHER"],
                "Modality": "MR",
                "SOPInstanceUID": "1.2.840.113619.2.5.1762583153.215519.978957063.124",
                "SeriesInstanceUID": "1.2.840.113619.2.5.1762583153.215519.978957063.121",
                "StudyInstanceUID": "1.2.840.113619.2.5.1762583153.215519.978957063.78"
              },
              "url": "dicomweb://s3.amazonaws.com/lury/MRStudy/1.2.840.113619.2.5.1762583153.215519.978957063.124.dcm"
            }
          ]
        }
      ]
    }
  ]
}
```

More info on this JSON format can be found here
[Issue #1500](https://github.com/OHIF/Viewers/issues/1500)

**Implementation Notes:**

<!-- 1. When hosting the viewer, you will also need to host a /viewer route on the server - or the browser may not be able to find the route. -->

1. For each instance url (dicom object) in the returned JSON, you must prefix
   the `url` with `dicomjson:` in order for the cornerstone image loader to
   retrieve it correctly. eg. `https://image-server/my-image.dcm` --->
   `dicomjson:https://image-server/my-image.dcm`
2. The JSON format above is compatible with >= v3.7.8 of the application in `V2`
   version. Older versions of the viewer used a different JSON format. As of
   20/04/20 the public [https://viewer.ohif.org/] is a pre 3.0 version that does
   not support this format yet.
3. The JSON format is case-sensitive. Please ensure you have matched casing with
   the naturalised Dicom format referenced in
   [Issue #1500](https://github.com/OHIF/Viewers/issues/1500).

_CORS Issues (Cross-Origin Resource Sharing)_

If you host a JSON API or Images on a different domain from the app itself,
you will likely have CORS issues. This will also happen when testing from
Localhost and reaching out to remote servers. Even if the domain is the same,
different ports, subdomains or protocols (https vs http) will also cause CORS
errors. You will to need add a configuration on each server hosting these assets
to allow your App server origin.

For example:

Let's assume your application is hosted on `https://my-ohif-server.com`.

Your JSON API is hosted on `https://my-json-api.aws.com`

And your images are stored on Amazon S3 at `https://my-s3-bucket.aws.com`

When you first start your application, browsing to
`https://my-ohif-server.com/myMode/dicomjson?url=https://my-json-api.aws.com/api/my-json-study-info.json`,
you will likely get a CORS error in the browser console as it tries to connect
to `https://my-json-api.aws.com`.

Adding a setting on the JSON server to allow the CORS origin =
`https://my-ohif-server.com` should solve this.

Next, you will likely get a similar CORS error, as the browser tries to go to
`https://my-s3-bucket.aws.com`. You will need to go to the S3 bucket
configuration, and add a CORS setting to allow origin =
`https://my-ohif-server.com`.

Essentially, whenever the application connects to a remote resource, you will
need to add the applications url to the allowed CORS Origins on that resource.
Adding an origin similar to https://localhost:3000 will also allow for local
testing.

### Securing Your Data

Coming soon

<!--
> Feeling lost? Securing your data is important, and it can be hard to tell if
> you've gotten it right. Don't hesitate to work with professional auditors, or
> [enlist help from experts](../help).

The OHIF Viewer can be configured to work with authorization servers that
support one or more of the OpenID-Connect authorization flows. The Viewer finds
it's OpenID-Connect settings on the `oidc` configuration key. You can set these
values following the instructions laid out in the
[Configuration Essentials Guide](./../configuration/index.md).

_Example OpenID-Connect Settings:_

```js
window.config = {
  ...
  oidc: [
    {
      // ~ REQUIRED
      // Authorization Server URL
      authority: 'http://127.0.0.1/auth/realms/ohif',
      client_id: 'ohif-viewer',
      redirect_uri: 'http://127.0.0.1/callback', // `OHIFStandaloneViewer.js`
      response_type: 'code', // "Authorization Code Flow"
      scope: 'openid', // email profile openid
      // ~ OPTIONAL
      post_logout_redirect_uri: '/logout-redirect.html',
    },
  ],
}
```

You can find an example of this setup in our
[User Account Control Deployment Recipe](./user-account-control.md).

#### Choosing a Flow for the Viewer

In general, we recommend using the "Authorization Code Flow" ( [see
`response_type=code` here][code-flows]); however, the "Implicit Flow" ( [see
`response_type=token` here][code-flows]) can work if additonal precautions are
taken. If the flow you've chosen produces a JWT Token, it's validity can be used
to secure access to your Image Archive as well.

 -->

### Recipes

We've included a few recipes for common deployment scenarios. There are many,
many possible configurations, so please don't feel limited to these setups.
Please feel free to suggest or contribute your own recipes.

- [Build for Production](./build-for-production.md)
- [Static](./static-assets.md)
- [Nginx + Image Archive](./nginx--image-archive.md)
- [User Account Control](./user-account-control.md)

<!--
  Links
  -->

<!-- prettier-ignore-start -->
[viewer-npm]: https://www.npmjs.com/package/@ohif/app
[pwa-url]: https://developers.google.com/web/progressive-web-apps/
[static-assets-url]: https://www.maxcdn.com/one/visual-glossary/static-content/
[app-store]: https://medium.freecodecamp.org/i-built-a-pwa-and-published-it-in-3-app-stores-heres-what-i-learned-7cb3f56daf9b
[dicom-web-standard]: https://www.dicomstandard.org/dicomweb/
[dicom-web]: https://en.wikipedia.org/wiki/DICOMweb
[host-static-assets]: https://www.netlify.com/blog/2016/05/18/9-reasons-your-site-should-be-static/
[cors]: https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS
[code-flows]: https://medium.com/@darutk/diagrams-of-all-the-openid-connect-flows-6968e3990660
[code-sandbox]: https://codesandbox.io/s/viewer-script-tag-tprch
<!-- prettier-ignore-end -->
