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Changes for page Multipart form-data

Last modified by Erik Bakker on 2024/06/17 11:39
From version 11.2
edited by Erik Bakker
on 2022/07/28 08:47
Change comment: Update document after refactoring.
To version 19.1
edited by Erik Bakker
on 2022/08/05 14:33
Change comment: There is no comment for this version

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1 -expert-data-handling-groovy-script
1 +Multipart form-data
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1 1  {{container}}{{container layoutStyle="columns"}}(((
2 -In the crash course on the API Gateway we discussed the various options available to [[secure>>doc:Main.eMagiz Academy.Microlearnings.Crash Course.Crash Course API Gateway.crashcourse-api-gateway-security.WebHome||target="blank"]] your API Gateway properly. In this microlearning, we will expand our knowledge on that topic by looking at a special case of securing your API Gateway. That case is special as you use an external identity provider (IDP) to govern the roles and users that have rights on your API Gateway.
2 +Sometimes when you call an external REST endpoint, they require you to send meta information and one or more "attachments" in one call to the REST endpoint. To make this possible, you need to send the information with the contentType called multipart/form-data. In this microlearning, we will discuss how you can configure a valid message within the eMagiz platform that allows you to send out messages with this contentType and have them accepted by the endpoint in question.
3 3  
4 4  Should you have any questions, please get in touch with [[academy@emagiz.com>>mailto:academy@emagiz.com]].
5 5  
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9 9  
10 10  == 2. Key concepts ==
11 11  
12 -This microlearning focuses on using an external IDP to validate whether a user is authorized to execute a certain action on your API Gateway and what configuration is needed in eMagiz to make this work.
12 +This microlearning focuses on configuring a multipart/form-data message within eMagiz to ensure it is sent correctly to an endpoint.
13 13  
14 -* The Token and Issuer URL of the external IDP need to be known
15 -* Users and Roles under User Management need to be manually configured and maintained to keep them in sync with the external IDP
14 +Key aspects are:
16 16  
17 -== 3. External IDP ==
16 +* Defining the boundary that separates the parts of the message
17 +* Defining the content types of each part of the message
18 +* Construction of the complete message according to the specification
18 18  
19 -In the crash course on the API Gateway we discussed the various options available to [[secure>>doc:Main.eMagiz Academy.Microlearnings.Crash Course.Crash Course API Gateway.crashcourse-api-gateway-security.WebHome||target="blank"]] your API Gateway properly. In this microlearning, we will expand our knowledge on that topic by looking at a special case of securing your API Gateway. That case is special as you use an external identity provider (IDP) to govern the roles and users that have rights on your API Gateway.
20 +== 3. Multipart form-data ==
20 20  
21 -When selecting the option OAuth2.0 (or OpenID Connect) you have the option to use the IDP provided by eMagiz which makes the configuration easy or you could use an external IDP which you have control over and want to use for this purposes.
22 +Sometimes when you call an external REST endpoint, they require you to send meta information and one or more "attachments" in one call to the REST endpoint. To make this possible, you need to send the information with the contentType called multipart/form-data. In this microlearning, we will discuss how you can configure a valid message within the eMagiz platform that allows you to send out messages with this contentType and have them accepted by the endpoint in question.
22 22  
23 -In this microlearning we will highlight what you need to configure in Design and Deploy to make this work within the tooling of eMagiz.
24 +Key aspects are:
24 24  
25 -=== 3.1 Design ===
26 +* Defining the boundary that separates the parts of the message
27 +* Defining the content types of each part of the message
28 +* Construction of the complete message according to the specification
26 26  
27 -On the security level of the API Gateway in Design you need to select the desired option, for example OAuth2.0. Instead of not filling in the token and issuer URL, indicating that you want to use the eMagiz IDP, you need to fill these in to reference the IDP of your choice. Below you see an example of how this could be configured.
30 +To actually construct the message there a several steps needed to make it work. Luckily, most of the steps needed have to do with concepts we have already discussed in previous microlearnings. As you can imagine based on what mulipart/form-data entails we need a way to both store the meta information and the file(s) we want to send to the external party. To do so it is advisable to put the metadata in one (or multiple) header(s) and use the file content as payload. This you can achieve with a header enricher and standard transformer.
28 28  
29 -[[image:Main.Images.Microlearning.WebHome@expert-securing-data-traffic-api-gw-security-external-idp-security-config-design.png]]
32 +Once the file content is your payload you need to make sure that the data is "raw" in nature. So when you have a base64 encoded string you should decode the string before sending it to the endpoint.
30 30  
31 -Note that the environmentID in this example should be replaced with an actual environmentID that references your environment.
34 +On top of that we need to define the contentType header as follows.
32 32  
33 -=== 3.2 Deploy ===
36 +[[image:Main.Images.Microlearning.WebHome@expert-data-handling-multipart-form-data--content-type-header-config.png]]
34 34  
35 -Normally, eMagiz will automatically update the User Management information based on the configuration in Design. However, because the identity check is not done by eMagiz but by an external party you need to manually enter the roles and users and configure the scope correctly on role level.
38 +After you have set the stage you can use a standard transformer component to build your message in the correct manner. To build it correctly you need to take the following into account:
36 36  
37 -To do so navigate to User Management in Deploy and add the users you want manually by pressing the New button and providing them with a name. Do subsequently the same for the roles. On role level do not forget to correctly enter the scope to make the call work. Note that the help text on the scope level gently reminds you what you need to do to make this work.
40 +* Each part of the message needs to be seperated by a boundary
41 +* The message needs to start with a boundary and finish with a boundary
42 +* Line breaks are needed to differentiate between the boundary and the text content
43 +* No line break is needed when the content is not text based
38 38  
39 -[[image:Main.Images.Microlearning.WebHome@expert-securing-data-traffic-api-gw-security-external-idp-scope-configuration.png]]
45 +Given all this you can write the following SpEL expression that will yield a desirable output:
40 40  
41 -{{warning}}When implementing this you would be the first to do so with this setup. This means there might be some unexpected behavior when configuring this.{{/warning}}
47 +{{code}}test{{/code}}
42 42  
49 +Most users would think that communication via queues to connect two separate eMagiz models is a bright idea. However, this is something that we do not encourage. We discourage this for several practical and technical reasons alike.
50 +
51 +When looking at the practical side of things getting it configured correctly is time-consuming and an error-prone action (as is evident by the question). Furthermore, it can lead to unexpected situations where you make a typo to listen to a queue on which no messages are provided. This queue will, however, be registered on the JMS level (when you activate the flow in question with the custom configuration), which can lead to confusing queue statistics and even more troublesome false-positive alerting based on missing queue metrics or missing consumers.
52 +
53 +On top of that, when you allow one model to write and read from queues registered in another model, maintaining both models will become very complex. This holds for the ones working on the project at the moment but also for those working on it at a later stage and does that need to provide (incidental) support on the environments.
54 +
55 +Another practical reason for not wanting this is that we do not actively support this use case from eMagiz. This means that when we update our technical infrastructure, we will not consider this scenario. This could lead to additional work in the future and reduced stability of your solution.
56 +
57 +From the technical point of view, the consequence of this construction is that both models need to know each other certificates and credentials, which are not considered secure. On top of that, because you, theoretically, can exchange data from any queue to any queue, you could create a situation in which updates in one model trigger changes in the other model (i.e., when using the same data model) that are unexpected (and frankly unwanted).
58 +
59 +We advise using functionality that makes it explicit that both models function independently of each other. From eMagiz, we consider two valid alternatives for this:
60 +- Using a web service as a communication layer between the two models. This web service can be REST or SOAP and has been implemented before
61 +- Using the Event Streaming functionality of eMagiz to write and read from topics.
62 +
63 +Both alternatives have the benefit that the security can be tight and explicit (i.e., only model A can write/post data to model B). Furthermore, managing the solution becomes much easier as it uses the standard functionality within the platform. Therefore, we have no plans to support this approach in the product.
64 +
43 43  == 4. Assignment ==
44 44  
45 -No assignment
67 +Consider what your criteria are when communicating between models and compare them to our criteria.
68 +This assignment can be completed with the help of the (Academy) project you created/used in the previous assignment.
46 46  
47 47  == 5. Key takeaways ==
48 48  
49 -* The Token and Issuer URL of the external IDP need to be known
50 -* Users and Roles under User Management need to be manually configured and maintained to keep them in sync with the external IDP
51 -* When implementing this you would be the first to do so with this setup.
72 +* Consider the following when communication between two models
73 +** Security
74 +** Loose coupling
75 +** Maintainability
76 +** Clarity
52 52  
53 53  == 6. Suggested Additional Readings ==
54 54  
55 -If you are interested in this topic and want more information, please read the help text provided by eMagiz.
80 +If you are interested in this topic please read the helptexts in the platform and read the following link:
56 56  
82 +* https://www.sobyte.net/post/2021-12/learn-about-http-multipart-form-data/
83 +
57 57  == 7. Silent demonstration video ==
58 58  
59 59  As this is more of theoretical microlearning, there is no video accompanying the microlearning.)))((({{toc/}}))){{/container}}{{/container}}