can't add a custom header

[mesheilah]

I've read your wiki on how to set a default header, but the class SDWebImageDownloader itself isn't available with SDWebImageSwiftUI namespace, or there is maybe some kind of necessary import that I'm not aware of ? plus, I need to pass a user token with some images but not all images in the app, so it's not going to be a default header set in AppDelegate, but rather a custom header for some cases, I couldn't find a way to a pass a custom header with SDWebImageSwiftUI

[dreampiggy]

You need :

import SDWebImageSwiftUI
import SDWebImage

The SDWebImageSwiftUI does not have a @_exported import SDWebImage to automatically do this.

Maybe I can added one in 1.3.2 version ? Any idea or PR ?

@mesheilah

[dreampiggy]

Maybe this can help: #100

---

Note: Previous version you don't need import SDWebImage as well, if you use CocoaPods or Carthage. This is SwiftPM's only issue because SwiftPM can not contains Swift && Objc code at the same target.

We already import SDWebImage in SDWebImageSwiftUI.h umbrella headers (available in CocoaPods && Carthage user)

[mesheilah]

@dreampiggy yeah I thought it was an issue with SwiftPM too. However, regarding the custom header thing, is there a way to include it for some images rather than in AppDelegate for all images ?

[dreampiggy]

Maybe I don't correctly understand your use case ?

You mean: "Can I choose only use A decoder to this URL, instead of register the coder plugin globally" ?

Use context option [.imageCoder : SDImageSVGCoder.shared] solve this.

or means the custom header for single image URL request ?

Use context option [.requestModifier : MyHTTPHeaderModifier] solve this.

[dreampiggy]

Request Modifier is a powerful tool beyond just HTTP header. You can modify the HTTP Method (for example, HEAD, POST, instead of default GET method), HTTP Body, allowsCellularAccess, allowsExpensiveNetworkAccess for low data mode, etc.

[mesheilah]

Type 'SDWebImageContextOption' has no member 'requestModifier' error fires

[mesheilah]

it must be downloadRequestModifier not requestModifier this change makes it compile.

[dreampiggy]

Sorry the strange naming :)...In the future this context option will become a Swift enum with associated value.

See more https://github.com/SDWebImage/SDWebImage/issues/2980

[mesheilah]

so to wrap up, a simple usage for this option is:

[.downloadRequestModifier: SDWebImageDownloaderRequestModifier(block: { (request) -> URLRequest? in
                    var request = request
                    request.setValue("MyValue", forHTTPHeaderField: "MyHeader")
                    return request
                })]

[dreampiggy]

Yes. Use Swift closure syntax can simply to

[.downloadRequestModifier: SDWebImageDownloaderRequestModifier {
    var request = $0
    request.setValue("MyValue", forHTTPHeaderField: "MyHeader")
    return request
}]

The request modifier is powerful, and can be reused. So this is why it design like that.

Maybe can have a single convience one like .HTTPHeader : ["Foo" : "bar"] which translate to this in future Swift API.

---

But things become complicated when you pass a Dictionary, because HTTP / 1.1 allows the Header Key and Value to CAPITAL.

However, HTTP 2.0 disable CAPITAL and must in lower cases. (See HTTP 2 Spec, or some blogs: https://blog.yaakov.online/http-2-header-casing/) So, if you write:

let options = [.HTTPHeader : ["Foo": "Bar", "foo" : "bar"]]

This will cause a misunderstanding...Actually there will be only one foo:bar in HTTP 2 request.

[dreampiggy]

@mesheilah 1.3.2 version released. Please upgrade, so that you don't need to manually import SDWebImage.

[dreampiggy]

@mesheilah SDWebImage 5.8.0 released. Which added the convenient API for HTTP header request/response modifier. See full changelog: https://github.com/SDWebImage/SDWebImage/releases/tag/5.8.0