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1 1  {{container}}{{container layoutStyle="columns"}}(((
2 -Within the crash course, we already explained XPath conceptually. In that same microlearning, we looked at some more uncomplicated cases of using XPath within your transformation. If you need to brush up on that knowledge, please check out this [[microlearning>>doc:Main.eMagiz Academy.Microlearnings.Crash Course.Crash Course Platform.crashcourse-platform-create-transformation-xpath-basic.WebHome||target="blank"]]. In the intermediate microlearning on this subject, we built upon that knowledge. Please check out this [[microlearning>>doc:Main.eMagiz Academy.Microlearnings.Intermediate Level.Create your transformations.intermediate-create-your-transformations-xpath-intermediate.WebHome||target="blank"]] if you need a refresher on that. In the [[microlearning>>doc:Main.eMagiz Academy.Microlearnings.Advanced Level.Create your transformations.advanced-create-your-transformations-xpath-advanced.WebHome||target="blank"]] that followed, we built upon that knowledge and looked at some concrete, practical examples that could be useful in your project. In this microlearning, we will wrap the concept of XPath by looking at three complex XPath alternatives that are sometimes needed when dealing with messages in eMagiz.
2 +Within the crash course, we already explained XPath conceptually. In that same microlearning, we also looked at some more uncomplicated cases of using XPath within your transformation. If you need to brush up on that knowledge, please check out this [microlearning](crashcourse-platform-create-transformation-xpath-basic.md). In the intermediate microlearning on this subject, we built upon that knowledge. Please check out this [microlearning](intermediate-create-your-transformations-xpath-intermediate.md) if you need a refresher on that. In this microlearning, we will build upon that knowledge and look at some concrete, practical examples that could be useful in your project.
3 3  
4 4  Should you have any questions, please get in touch with [[academy@emagiz.com>>mailto:academy@emagiz.com]].
5 5  
6 +* Last update: October 25th, 2021
7 +* Required reading time: 6 minutes
8 +
6 6  == 1. Prerequisites ==
7 7  
8 -* Expert knowledge of the eMagiz platform
11 +* Advanced knowledge of the eMagiz platform
9 9  * [[XPath Basic>>doc:Main.eMagiz Academy.Microlearnings.Crash Course.Crash Course Platform.crashcourse-platform-create-transformation-xpath-basic.WebHome||target="blank"]]
10 10  * [[XPath Intermediate>>doc:Main.eMagiz Academy.Microlearnings.Intermediate Level.Create your transformations.intermediate-create-your-transformations-xpath-intermediate.WebHome||target="blank"]]
11 -* [[XPath Advanced>>doc:Main.eMagiz Academy.Microlearnings.Advanced Level.Create your transformations.advanced-create-your-transformations-xpath-advanced.WebHome||target="blank"]]
12 12  
13 13  
14 14  == 2. Key concepts ==
15 15  
16 -This microlearning focuses on very complex XPath operations.
18 +This microlearning focuses on more complex XPath operations.
17 17  
18 -With XPath Expert, we mean learning that XPath options are sometimes very complex but could benefit you in specific cases in your daily work.
20 +With XPath Advanced, we mean learning that XPath options are complex but could benefit you in your daily work.
19 19  
20 -Some of the very complex XPath options are:
22 +Some of the more complex XPath options are:
21 21  
22 -* matches
23 -* replace
24 -* tokenize
24 +* dateTime calculation
25 +* Filter list
26 +* XPath on JSON
27 +* SpEL notation for XPath
25 25  
26 -== 3. XPath Expert ==
27 27  
28 -Within the crash course, we already explained XPath conceptually. In that same microlearning, we looked at some more uncomplicated cases of using XPath within your transformation. If you need to brush up on that knowledge, please check out this [[microlearning>>doc:Main.eMagiz Academy.Microlearnings.Crash Course.Crash Course Platform.crashcourse-platform-create-transformation-xpath-basic.WebHome||target="blank"]]. In the intermediate microlearning on this subject, we built upon that knowledge. Please check out this [[microlearning>>doc:Main.eMagiz Academy.Microlearnings.Intermediate Level.Create your transformations.intermediate-create-your-transformations-xpath-intermediate.WebHome||target="blank"]] if you need a refresher on that. In the [[microlearning>>doc:Main.eMagiz Academy.Microlearnings.Advanced Level.Create your transformations.advanced-create-your-transformations-xpath-advanced.WebHome||target="blank"]] that followed, we built upon that knowledge and looked at some concrete, practical examples that could be useful in your project. In this microlearning, we will wrap the concept of XPath by looking at three complex XPath alternatives that are sometimes needed when dealing with messages in eMagiz.
29 29  
30 -Some of the very complex XPath options are:
31 +== 3. XPath Advanced ==
31 31  
32 -* matches
33 -* replace
34 -* tokenize
33 +Within the crash course, we already explained XPath conceptually. In that same microlearning, we also looked at some more uncomplicated cases of using XPath within your transformation. If you need to brush up on that knowledge, please check out this [[microlearning>>doc:Main.eMagiz Academy.Microlearnings.Crash Course.Crash Course Platform.crashcourse-platform-create-transformation-xpath-basic.WebHome||target="blank"]]. In the intermediate microlearning on this subject, we built upon that knowledge. Please check out this [[microlearning>>doc:Main.eMagiz Academy.Microlearnings.Intermediate Level.Create your transformations.intermediate-create-your-transformations-xpath-intermediate.WebHome||target="blank"]] if you need a refresher on that. In this microlearning, we will build upon that knowledge and look at some concrete, practical examples that could be useful in your project.
35 35  
36 -=== 3.1 matches ===
35 +Some of the more complex XPath options are:
37 37  
38 -Sometimes, you want to determine whether a specific value within your payload matches a pattern. In those cases, you can use the XPath function called matches. The function will return true if the supplied string matches a given regular expression. So, for example, if you want to check whether your OrderID contains exactly seven digits and nothing else, the following XPath expression will work for your use case.
37 +* dateTime calculation
38 +* Filter list
39 +* XPath on JSON
40 +* SpEL notation for XPath
39 39  
40 -matches(OrderID,'^\d{7}$')
42 +=== 3.1 dateTime calculation ===
41 41  
42 -As a result, you will get a true or false back which you can then use as a filter or within an if-then-else construction.
44 +Sometimes we see that a dateTime calculation is needed within a transformation to determine a specific action. As these calculations are not natively supported within the eMagiz platform, you need to use XPath's functionality to calculate the new valid date (or dateTime).
43 43  
44 -=== 3.2 replace ===
46 +The XPath standard offers several functions to calculate with dateTime values. The two most used options are dayTimeDuration and yearMonthDuration. With the help of the dayTimeDuration, you can add, subtract, multiple, or divide seconds, minutes, hours, and days regarding the original value. The yearMonthDuration works similarly but then for months and years. An example of such an XPath is: <xsl:value-of xmlns:xs="http://www.w3.org/2001/XMLSchema" select="CDM:StartDate + xs:dayTimeDuration('P1D') * xs:yearMonthDuration('P1M')"/>. In this example, XPath adds one day and subtracts one month from the input date. Note that making this work requires the additional namespace to be defined. Therefore you need a custom snippet within your transformation or a custom transformation to make this work. Furthermore, note that the P1D and P1M could also be filled with the help of parameters to make them dynamic in nature.
45 45  
46 -The replace function has many similarities with the matches function. It builds on the premise of the matches function, but instead of returning a true or false, you can state with what you want to replace the matched string. In other words, this function returns a string produced from the input string by replacing any substrings that match a given regular expression with a supplied replacement string.
48 +Some examples that we saw during the years:
47 47  
48 -When we apply this to our earlier example, we can state that when the OrderID contains any non-digit, we will replace this value with nothing. This will lead to the following XPath expression.
50 +* https://my.emagiz.com/p/question/172825635700358186
51 +* https://my.emagiz.com/p/question/172825635700352588
49 49  
50 -replace(OrderID,'\D','')
53 +=== 3.2 Filter list ===
51 51  
52 -With a given input string of 12C34A567, the returned result will be 1234567.
55 +Sometimes you have a large message which contains a certain list within it. However, logic dictates that you can only send the message if at least one entry in the list for which attribute A is filled and attribute B equals type C. To make that happen in XPath, we first need to navigate to the list within the message. As we previously learned, there are two options to do so. One is to use // to navigate to the entity somewhere in the tree directly. The other is to start at the root and walk the tree from there. In this example, we use the latter. That results in the following XPath example: /root/list[attributeB = 'type C']/attributeA !=''. With this XPath, you filter the list on the specified check and subsequently check whether one of those entries that remains has an attributeA which is filled in.
53 53  
54 -=== 3.3 tokenize ===
57 +=== 3.3 XPath on JSON ===
55 55  
56 -The tokenize function can split a string into multiple entries for you. This is particularly useful when you want to match an input string to a list of possible values that are valid for that string. For example, the function returns a sequence of strings constructed by splitting the input wherever a separator is found; the separator is any substring that matches a given regular expression.
59 +With the release of build number .50, we expanded our offering on JSON messages to resemble much of the functionality we previously offered for XML messages. As a result, you can use XPath expressions on JSON messages within the following components (related to XPath):
57 57  
58 -So, for example, when the input string for AddressID is "street,housenumber,housenumberaddition" and you want to tokenize this with the help of the separator, you could use, in this example, the comma between the values as the separator. This will lead to the following XPath expression.
61 +* XPath header enricher
62 +* XPath transformer
63 +* XPath router
59 59  
60 -tokenize(AddressID,',')
65 +To activate the functionality, simply link the JSON source factory support object to one of these components to achieve the desired result. For more information, check out: https://emagiz.github.io/docs/release-notes/build50.
61 61  
62 -The given input detailed above will result in the following output: street housenumber housenumberaddition.
67 +=== 3.4 SpEL notation for XPath ===
63 63  
69 +Sometimes you want to perform an XPath operation but store the header via a standard message header enricher component. As a result, you need a valid SpEL expression to help you in this cause. To do so, you need to know the correct notation for an XPath expression when using the SpEL language. An example of the correct notation is: #xpath(payload,'/root/entity/attribute')
70 +
64 64  == 4. Assignment ==
65 65  
66 66  Check out which of the XPaths we have discussed today can be found within your project.
... ... @@ -68,19 +68,18 @@
68 68  
69 69  == 5. Key takeaways ==
70 70  
71 -Some of the very complex XPath options are:
78 +Some of the more complex XPath options are:
72 72  
73 -* matches
74 -* replace
75 -* tokenize
80 +* dateTime calculation
81 +* Filter list
82 +* XPath on JSON
83 +* SpEL notation for XPath
76 76  
77 77  == 6. Suggested Additional Readings ==
78 78  
79 -If you are interested in this topic and want more information on it, please read the help text provided by eMagiz and read more information on the following links:
87 +If you are interested in this topic and want more information on it, please read the help text provided by eMagiz and read more information on the following link:
80 80  
81 -* http://www.xsltfunctions.com/xsl/fn_matches.html
82 -* http://www.xsltfunctions.com/xsl/fn_replace.html
83 -* http://www.xsltfunctions.com/xsl/fn_tokenize.html
89 +* https://www.w3schools.com/xml/xpath_intro.asp
84 84  
85 85  == 7. Silent demonstration video ==
86 86